Question

2nd & 4th term of an AP is 12
and 20 repectively find the sum of first 25 terms​

Answer 1

a+d=12-----(1)

a+3d=20-------(2)

equ (2) -(1)

2d=8

d=4

Putting the Value of d in equ (1)

a+d=12

a+4=12

a=12-4

a=8

a +(25-1) d=8+24*4=8+96

= 104

Answer=104***********