Question

Find the sum of the first 20 terms of an arithmetic progression whose first term is 5 and last term is 295.

Answer 1

Answer:

Given,

First term, a=3 and last term, l=57

And,n=20

S=n/2(a+l)

=20/2(3+57)

=10(60)

=600

Answer 2

Answer:

The sum of the first 20 terms is 3000 .

Step-by-step explanation:

First term (a)= 5

last term (I) = 295

number of terms (n)= 20

so, the sum of first 20 terms is

S = n×(a + I)/2

=>S = 20×(5 + 295)/2

=> S = 3000