Question

The sum of first 25 terms in an A.P. is 525.And the sum of next 25 terms of the same A.P. is 725 What is common difference?​

Answer 1

this is diffficult........ .............

Answer 2

Explanatory Answer

The sum of the first 25 terms, S25 = 525

The sum of the next 25 terms, K25 = sum of next 25 terms = 725

a26 = a1 + 25d

a27 = a2 + 25d

K25 = a26 + a27 + ...... + a50

Or K25 = a1 + 25d + a2 + 25d + ...... + a25 + 25d

Or K25 = a1 + a2 + ...... + a25 + 25(25d)

Or K25 = S25 + 25(25d)

i.e., 725 = 525 + 25 x 25d

200 = 25 x 25d

8 = 25d

d = 8/25