DELHI PUBLIC SCHOOL
HYDERABAD
CLASS: XI
SUBJECT: MATHEMATICS(REGULAR/APPLIED)
CHAPTER: GEOMETRIC SEQUENCE (WORK SHEET)
Answer the following:
1. Find the 5 th term from the end of the sequence 2, 6, 18, ……39366.
13
2. The sum of three numbers in G.P. is and their product is -1. Find the numbers.
12
3. The first term of a G.P. with real terms is 1. If the sum of its third and fifth terms is 90,
find the common ratio of the G.P.
3
4. Find the number of terms of a G.P. whose first term is 4, common ratio is 2 and the last
term is 384.
5. If k, 2k+2, 3k+3, ….. are in G.P. , then find the common ratio of the G.P.
6. The fourth term of a G.P. is the square of its second term and the first term is -3.
Determine its seventh term.
7. Given a G.P. with a = 729 and 7 th term = 64, determine 𝑆7 .
3 3 3069
8. How many terms of the sequence 3, 2 , 4 , …..are needed to give the sum ?
512
9. The sum of some terms of a G.P. is 315 whose first term and the common ratio are 5 and
2 respectively. Find the last term and the number of terms.
10. The n th term of a G.P. is 128 and the sum of its n terms is 255. If its common ratio is 2,
then find its first term.
11. Find the first term of the G.P. whose common ratio is 3, last term is 486 and the sum of
whose terms is 728.
31
12. If the first term of a G.P. is 5 and the sum of the first three terms is , find the common
5
ratio.
13. The sum of first three terms of a G. P. is to the sum of first six terms as 125: 152. Find the
common ratio of G.P.
4 27
14. Insert 4 Geometric means between 9 and .
8
15. The A.M. between two numbers is 34 and G.M. is 16. Find the numbers.
3
16. The sum of an infinite G.P. is 16 and the sums of the squares of its terms is 1535. Find the
common ratio and the fourth term of the progression.
Answers:
3 4 4 3 3
1). 486 2) 4 , -1, 3 or , -1, 4 3) ± 3 4) 10 5) 2 6) -2187 7) 463 8) 10 9) 160, 60
3
1 6 3 2 3 9 1 3
10) 1 11) 2 12) 5 or - 13) 14) 3 ,1, 2 , 4 15) 4, 64 16) 4 , 16
5 5
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