Question

the first term of an AP is 5the last term is 45 and the sum is 400,find the number of term and commen differences

Answer 1

a=5

l=45

sum=400

Sum=n/2(a+l)

400=n/2(5+45)

400=n/2(50)

400=25n

n=400/25

n=16

Number of terms=16

Common difference

a+4d=5

a+44d=45

-40d=-40

d=1

So,the common difference is 1.