Question

the sum of 10th and 16th term of an Arithmetic progression is 10 the comman difference is -9 Find it's 15th term . a15 =
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Answer 1

Answer:

- 13

Explanation:

Let the first term of the AP is a

Then, A/Q,

a + 9×(-9) + a + 15×(-9) = 10

Or, 2a - 81 - 135 = 10

Or, 2a = 10 + 81 + 135

Or, 2a = 226

Or, a = 226/2

Or, a = 113

Therefore the 15th term of AP is

a + 14d

= 113 + 14×(-9)

= 113 - 126

= - 13 Ans.