Question

Find the sum of n terms of an ap whose nth term is 5n-1

Answer 1

Answer:

Step-by-step explanation:

nth term = 5n - 1

Put n=1, we get

1st term = 5-1 = 4

Hence sum of n terms = n(First term + nth term)/2

= n(4+5n - 1)/2

= n(5n +3)/2