Question

If the nth term of an Ap is (5n-3)
find the sum of first 20 terms of the
Ap using formula​

Answer 1

I don't know the answer of this question

Answer 2

Step-by-step explanation:

given , nth term of AP = 5n-3

=> first term = 5×1-3 = 2

=> 20th term = 5×20-3 = 97

=> sun of first 20 terms of given AP

S20= (20/2) (2+97)

= 10×99

= 990

formula used:- if a and l are 1rst and nth terms

respectively

Then sum of first n terms

Sn = (n/2) ( a+l)