Log in to add a comment

Log in to add a comment

For this AP,

First Term, a = 5

Common Difference, d = 8-5 = 3

No. of terms, n = 60

Sum of first n terms, Sn

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

∴S₆₀ = 60/2 (2(5) + (60 - 1)*3)

= 30 (10 + 59 * 3)

= 30 (10 + 177)

= 30 * 187

∴

Thus, sum of first 60 terms of the A.P. is 5610.