Question

10. The sum of third and fifth terms of an AP is 30. And the sum of fourth
and eighth term of the same AP IS 46. Find the sum of first 10 terms
of this AP,
​

Answer 1

a3+a5=30

a8=46

a+2d+a+4d=30

2a+6d=30

a+3d=15---->1

a+7d=46---->2

upon solving both we get

-4d= -31

d=31/4

=> a=-33/4

Sn =n/2(2a+(n-1)d

Sub values in formula to get S10

Answer 2

The correct answer is 210 of this question.