Question

2) The first term of an Arithmetic Progression is
7 and the common difference is 4. To find the
sum of first 25 terms, complete the following
activity.
Activity : Here, a=7, d=4, n=25, S25 = ?
By formula,
.
​

Answer 1

Answer:

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

Sn=25/2(2*7+(25-1)4)

Sn=25/2(14+(24)4)

Sn=25/2(14+96)

Sn=25/2(110)

Sn=25*55

Sn=1375