Question

The first and the last term of an ap is 5 and 45 respectively and the sum is 400 find the number of terms

Answer 1

Step-by-step explanation:

First term, a=5

Last term, l=45

Common difference = d

Sum of AP of n terms = (n/2)(a+l)

Sum = 400

On substituting values of a & l,

We get, n=16

l=a+(n-1)d

On substituting values of a,l & n

We get, d= 8/3