Solution
Solution
CLASSROOM
                          HANDOUT (I-V)
SOLUTIONS
DELHI CENTRE:           DELHI CENTRE:            DELHI CENTRE:            PRAYAGRAJ CENTRE:          JAIPUR CENTRE:
Vivekananda House       Tagore House             Mukherjee Nagar          31/31 Sardar Patel Marg,   Plot No. 6 & 7, 3rd Floor,
6-B, Pusa Road,         27-B, Pusa Road,         637, Banda Bahadur       Civil Lines, Prayagraj     Sree Gopal Nagar,
Metro Pillar No. 111,   Metro Pillar No. 118,    Marg, Mukherjee Nagar,   Uttar Pradesh-211001       Gopalpura Bypass,
Near Karol Bagh Metro   Near Karol Bagh Metro    Delhi-110009             Phone: 9958857757          Jaipur-302015
New Delhi-110060        New Delhi-110060         Phone: 9311667076                                   Phone: 9358200511
Phone: 8081300200       Phone: 8081300200
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2 |       CSAT HANDOUT : SOLUTIONS
                         CLASS - I : SOLUTIONS
  1.    (c)             Number = 2k, 3k                                Statement-II:
                           LCM = 2 × 3 × k = 48                                LCM (4, 5, 6, 15) = 60
                                   k = 8                                                Number = 2520 = 2497 + 23
                      Numbers = 16, 24                                 Hence statement (II) is incorrect.
                            Sum = 40                                   Hence option (a) is correct.
           Shortcut  2 + 3 = 5 only 40 is divisible by 5.
                                                                  6.   (d)
                                                                       Number = 13k + 3
  2.    (d)             Number = LCM(5, 8, 12, 30)k + 2                When divided by 5, R = 2
                                    = 120k + 2                         13k + 3 = 5y + 2
                           For k = 2 Number                              13k + 1 = 5y
                                    = 242 – divisible by 11
                                                                              13 k  1
                                                                         y=
  3.    (a)                                                                      5
                                                                       For k = 3,      13(3) + 3 = 42
        Remainder:             4       5
Remainder which is equal to that number will be: 8. (c) Number = LCM(15, 20, 25, 35) – 10
        We get 18, 38, 58, 78, 98, 118 when value of n is 1, 2,   9.   (b)              Number = LCM(3, 4, 5, 6)k + 2
        3, 4, 5 and 6 respectively. Highest double digit such
                                                                                                  = 60k + 2
        number will be
                                                                       For k = 17,      Number = 1022
  4.    (c)
                                                                  10. (a) Number = LCM(5, 6, 8, 12)k + 1
        Statement-I: Number = LCM(18, 24, 36) + 7
                                                                             = 120k + 1  divisible by 13
                                    = 72 + 7 = 79
                                                                       For k = 4,       Number = 481
        Hence statement (I) is correct.
                                                                  11. (a)              Distance = LCM(40, 42, 45)
        Statement-II: Number = LCM(8, 12, 16) – 3
                                                                                                  = 2520 cm = 25 m 20 cm
                                  = 48 – 3 = 45
        Hence statement (II) is correct.                          12. (a) LCM(2, 3, 4, 5, 6) = 60
        Hence option (c) is correct.                                         Number of times they meet in 180 days = 3
                                                                             (On 1st, 61st and 121st day)
  5.    (a)
        Statement-I: Number = LCM(56, 98) + 2                     13. (c) LCM(6, 7, 8, 9, 12) = 504 sec
                                    = 392 + 2 = 394                          1 hour = 3600 sec
        Hence statement (I) is correct.                                Total times = 8 (including the time when they started
                                                                       firing together)
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                        CLASS - II : SOLUTIONS
  1.    (b)                                                              LCM of (2, 3, 4, 5, 6)
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      14 + x – 4 = 11k or 0                                   So, A = 6
      x + 10 = 11
                                                         9.   (d)
      x = 1 (For x = 1 number will be divisible by 11)
                                                              15 B is divisible by 6.
4.    (a&c)                                                   So B should be even number
      Divisibility rule for 2, 3, 6
                                                              also 1 + 5 + B should be divisible by 3
      Rule-2 : unit place even
      Rule-3 : sum divisible by 3                             So only 6 is the value for B.
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                         CLASS - IV : SOLUTIONS
                                                           5.   (a) 4% = 0.04            (b) 11% = 0.11
          1                         2    2
1.    (a)   = 50%                (b)  66 %
          2                         3    3                            2
                                                                (c) 17 % = 0.174         (d) 19% = 0.19
               3                    5    1                            5
      (c)         75%           (d)  83 %
               4                    6    3
                                                                       3
                                                                (e) 185 % = 1.8575
          8      2               9                                     4
      (e)   = 114 %           (f) = 180%
          7      7               5
                                                                (f) 223% = 2.23
               23       1     55                                (g) 12650% = 126.50
      (g)         = 209 % (h)    = 250%
               11      11     22
                                                                          7
                1                           3                   (h) 876543 % = 8765.43875
2.    (a) 20% =                  (b) 30% =                                8
                5                          10
                                                           6.   (a) 0.14 = 14%          (b) 0.23 = 23%
                13                         17
      (c) 65% =                  (d) 85% =                      (c) 0.768 = 76.8%       (d) 0.815 = 81.5%
                20                         20
                                                                (e) 3.84 = 384%          (f) 4.89 = 489%
                          3                   1
      (e) 115% = 1            (f)225% = 2
                         20                   4                 (g) 123.75 = 12375% (h) 678.54 = 67854%
                    21                                39                      15
      (e) 84% =                   (f) 156% =               9.   % change =        100%  25%
                    25                                25                      60
                     18                       23                              30
      (g) 360% =              (h)1150% =                   10. % change =         100%  20%
                      5                       2                              150
                                            1                                     22000
4.    (a) 1 : 10 = 10%        (b)2 : 15 = 13 %             11. (i) % salary =            100%  88%
                                            3                                     25000
                    4                         20                                  25000
      (c) 3 : 35 = 8 %        (d)5 : 84 = 5      %              (ii) % salary =          100% = 113.63%
                    7                         21                                  22000
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10 |           CSAT HANDOUT : SOLUTIONS
                2.25                                          y = 90% of x
        Loss% =       100%  2.25%
                100                                       24. (b)
        Method-II:                                            B = 0.95 A and also
                                                              A = B + 20
                15  15
        Loss% =         % = 2.25%                              A = 0.95A + 20
                 100
                                                                          20
  19. Method-I:                                                     A=        = 400
                                                                         0.05
      Let price be a                                                B = 380
      ATQ, a(1.2)(0.9) = 54
                                                          25. (b)
        a = Rs. 50
                                                              80% = 12 km
        Method-II:
                                                                         12
                               (20)( 10)                     100% =         100 = 15 km
        % change = 20  10               = 8% increase                  80
                                  100
        54 = 1.08 (original price)                        26. (b)
        Original price = Rs. 50                               Let the number of boys and girls be x and y
                                                              respectively.
  20. Method-I:
                                                              Total sum of ages of boys = 20 x and total sum of
        Original area = 200 × 100    cm2                      ages of girls = 16y
        New area = 160 × 90 cm2                               Given that, 20x + 16y/(x+y)=18
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12 |           CSAT HANDOUT : SOLUTIONS
                       CLASS - V : SOLUTIONS
  1.    (b)                                                                                    15x = 60
        Expense = Price × Quantity consumed
                                                                                                x = 4
        (Price × Quantity)original = 1.25 × Price × Quantitynew
                                                                                 Passing marks = 25x + 40 = 140
         4
           Q original = Qnew = 80% of original                                                            140
         5                                                                               Pass% =               100% = 35%
                                                                                                          400
        i.e., consumption must decrease by 20%.
  2.    (a)                                                       7.   (b)
        Milk = 35% of 200gm = 70gm                                     Let total marks = 100x
        Water = 130gm                                                  A.T.Q.,         56x – 66 = 84x – 234
        New water = 130 + 80 = 210 gm                                                          28x = 168
                    70                                                                          x = 6
        % milk =         100% = 25%
                    280                                                          Passing marks = 56x – 66 = 270
  3.    (c)                                                       8.   (a)
                                                                       Let original price = 100
                      45x
                           27 = 36                                    Original expense = 100 × 30 = 3000
                      100
                                                                       New expense = 3300
                             45x = 900
                                                                       New price = 132
                                x = 20
                                                                                         3300
  4.    (b)                                                            New quantity =         = 25
                            0.1Q = 0.2R
                                                                                         132
                                   = 0.2(10000) = 2000            9.   (d)
                               Q = 20000                               Let maximum marks of each paper be 100
                           0.05P = 0.15Q = 3000                        Total marks = 500
                               P = 60000                               Marks scored = 300 = 6x + 7x + 8x + 9x + 10x
                       P + Q + R = 90000                                                       40x = 300
  5.    (d)                                                                                     x = 7.5
          Original petrol price = 100                                                    Marks = 45, 52.5, 60, 67.5, 75
                New petrol price = 140                            10. (c)
                  Original usage = 100                                Let total employees = 100
                     New usage = x
                                                                                                  100
                Original expense = 100 × 100 = 10,000
                   New expense = 140x = 1.05(10000)                                        40          60
                                                                                          Males      Females
                                x = 75
                                       25                                               30         10
                  So, % decrease =         100% = 25%                                Salary     Salary
                                      100                                             30000     30000
  6.    (d)
        Let total marks = 100x                                         45 employees = salary  30000
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                                                             CSAT HANDOUT : SOLUTIONS                 | 13
                              60                  16. (d)
                            Females
                                                      Let A’s weight = 100
                           15          45             B’s weight = 60
                         30000     < 30000
                                                                                   60
                         Salary     Salary            % decrease in weight =            100% = 37.5%
      75% of female employees earn < 30000.                                        160
                                                  17. (a)
11. (a)
                                                             Amount he has = 75% = 9000
    Water = 4950 gm
                                                                       25% = 3000
      Rest = 50 gm
                                                      So he needs 1,000 more.
                         water
      New mass = x                                18. (b)
                         rest = 50gm = 2%
                                                      (1.25 price) (Quantity – 6) = 1200
      100% = 2500 gm
                                                      and Price × Quantity = 1200
      water = 2450 gm
                                                      1.25(1200) – (1.25 × 6) Price = 1200
12. (c)
                                                              5
    Wage bill = 300 × w                               300 =      6  price
                                                              4
      New wage bill = 345 × 0.8w                      Rs. 40 = Price
                         345  0.8 
      % change =  1                100%        19. (c)
                           300 
      = 8% decrease                                   60 marks = 40%
                                                      Maximum marks = 100% = 150
13. (a)                   Milk = 324l
                         Water = 36l              20. (c)
         (324 + 36 + x) × 19% = 36 + x                            40% men = 30% women
                   (360 + x)19 = 100(36 + x)                        4 × men = 3 × women
                                                      Let women = 100x
                            81x = 3240
                                                          men = 75x
                                  x = 40l             Married people = 30x + 30x = 60x
14. (a)                                                                               60x
                                                      % married population =               100%
    Let total voters = 100x                                                          175x
      Voters voted = 75x                                                                2
                                                                                   = 34 %
      Valid votes = 70x                                                                 7
      C = 1.4B = B + 84000                        21. (b)
                          0.4B = 84000               Pricefinal = Priceoriginal × (1.25)(0.8)(1.1)
                                                      = 1.1 Priceoriginal
                                  B = 210000
                                                      = 110% of original
                                  C = 294000
      A = 40x                                     22. (a)
      B + C = 70x – 40x = 30x                                           0.7x + y   =   1.65y
                                                                              7x   =   6.5y
      So A got maximum votes.
                                                                        z + 0.6x   =   1.65z
15. (b)                                                                       6x   =   6.5z
    Households between 30000 – 100000 = 66%           x < y, x > z
                           66% = 990 households       y>x>z
                             1% = 15 households   23. (d)
               Between 1L – 2L = 22% – 6% = 16%       Let A = 100, B = 50, then
                                    = 240
                                                      P = 40% of 100 + 65% of 50
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14 |           CSAT HANDOUT : SOLUTIONS
                40          65                                                          x
        =           100       50                     Proportion of females =
               100         100                                                         xy
        = 40 + 32.5 = 72.5                              No. of males in office B = x
        Q = 50% of 100 + 50% of 50                      No. of employees in office B = 1.5(x + y)
                50          50                                                                  x
        =           100       50                     Proportion of females = 1 
               100         100                                                             1.5( x  y )
        = 50 + 25 = 75
                                                        Hence, percentage of males in the overall
        Here, P < Q
                                                                                       (x  y )
        Again, let A = 101, B = 100, then               employee group =
                                                                               ( x  y )  1.5( x  y )
        P = 40% of 101 + 65% of 100
           40          65                                      1
        =      101       100                         =         = 40%
          100         100                                     2.5
 W = 32 kg
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