JEE Main20266 April 2026Morning ShiftMathematicsSequences and SeriesActual
The sum of the first ten terms of an A.P. is 160 and the sum of the first two terms of a G.P. is 8 . If the first term of the A.P. is equal to the common ratio of the G.P. and the first term of the G.P. is equal to common difference of the A.P., then the sum of all possible values of the first term of the G.P. is:
Options
- A34 9
- B34 13
- C32 9
- D32 13
Correct answer
A. 34 9
Step-by-step solution
Let the first term of the A.P. be a and its common difference be d . Let the first term of the G.P. be A and its common ratio be R . Given that the sum of the first ten terms of the A.P. is 160 : 10 2 [2a + (10 - 1)d] = 160 5(2a + 9d) = 160 2a + 9d = 32 Given that the sum of the first two terms of the G.P. is 8 : A + AR = 8 A(1 + R) = 8 We are also given that a = R and A = d . Substituting these into the first equation: 2R + 9A = 32 R = 32 - 9A 2 Substitute R into the second equation: A (1 + 32 - 9A 2 ) = 8 A ( 2 +