Question

The first term of an ap is 5 and the last term is 45 and the sum is 400 . Find
the number of terms and the cd

Answer 1

Step-by-step explanation:

a=5

last term=45

sum=n/2{first term+last term}

400=n/2{5+45}

400=n/2×50

n=400×2/50

n=16

number of terms=16

last term=a+(n-1)d

45=5+(16-1)d

40=15d

d=40/15

d=8/3