2021-2022 CLASS 10 (2020-2021) (Subjective Worksheet)
ARITHMETIC PROGRESSIONS
Q. 1 If 9th term of an A.P. is zero, prove that the 29th term is double the 19th
term?
Q. 2 If a1, a2, a3…….a24 are in AP, a1 + a5 + a10 + a15 +a20 + a24 =30 then
Find a1 + a2 + a3 +…….a24 .
Q.3 Interior angles of a polygon are in A.P. If the smallest angle is 120 ° and
common difference is 5°, find the number of sides of the polygon.
Q. 4 If (a)2,(b)2,(c)2 are in A.P., then show that : , are in A.P.
Q. 5. Find the sum of the first 30 terms of an A.P., whose nth term is 2–3n.
Q. 6 If mth and nth terms of an A.P. are 1/n and1/m respectively, then
find the sum of mn terms
Q.7 If the pth, qth & rth term of an AP is x, y and z respectively,
show that x(q-r) + y(r-p) + z(p-q) = 0
Q. 8. If the roots of the equation a(b – c) x2 + b(c – a) x + c (a – b) = 0 are
equal, then show that 1/a , 1/b , 1/c are in A.P.
Q. 9. If Sn denotes the sum of first n terms of an A.P.,
Prove that S12 =3(S8 – S4)
Q.10. If , are in A.P. then show that (b−c)2,(c−a)2,(a−b)2 are in A.P.
Q. 11. The sum of four consecutive numbers in A.P. is 32 and the ratio of the
product of the first and last terms to the product of two middle terms is 7 : 15.
Find the number
Q. 12. The ratio of sum to n terms of two A.P.’S is 3n + 4 5n + 6. Then find
the ratio of their 15 th terms.
Q .13.If pth term of an A.P. 1/q and qth term is 1/p. prove that the sum of the first ‘
pq’ terms is 1/2(pq +1).