Question

A class consists of number of boys whose ages are in AP the common difference being 4 months if the youngest boys is 8 years and if the sum of Ages is 168 years then the number of boys are

Answer 1

Step-by-step explanation:

First term=age of youngest boy=8=a

a=8

d=4 months= 124 years= 31 years

S n =n. 2a+(n−1)d / 2 =168

⇒n⋅ 216+(n−1) 31=168

⇒n⋅ 2⋅3 / 48+(n−1)1 =168

⇒48n+n 2 −n=6×168

⇒n 2 +47n−1008=0

⇒(n−16)(n+63)=0

n=16 or −63

∵n≥0, because it is no. of persons

∴n=16

The no. of persons is 16