Question

the first tearm of an AP is 7, the last term is 47 and the sum is 432 find number of terms and common difference. please step by step​

Answer 1

Answer:

a=7 l=49 Sn=420

Sn=

2

n

[a+l]

So 420×2=n[7+49]

n=15

l=a+(n−1)d

⇒ 49=7+14 d

⇒ 7=1+2 d ⇒ 2d=6

⇒ d=3