Question

The ages of the students in a class are in AP,
whose common difference is 4 months. If the
youngest student is 8 yr old and the sum of the
ages of all the students is 168 yr, then find the
number of students in the class.​

Answer 1

Step-by-step explanation:

4 months=0.3 year.

Sn=n/2[2a+(n-1)d]

168=n/2[2(8)+(n-1)0.3]

168×2=n[16+(n-1)0.30

336=16n+(n-1)0.3n

Multiply both sides by 10.

3360=160n+3n^2-3n

3n^2+157n=3360.