Question

how many terms have to be considered for getting the sum 5740 in the A.P 7, 14, 21........,?​

Answer 1

Answer:

Given:-

Sn=5740 and

Ap=7,14,21............?

d=a2-a1=14-7=d=7.

a=7.

To find,

n=?

Sn=2a+(n-1)d

5740=2(7)+{n-1}7

5740-14=n-1×7

5726=n-1×7

5726/7=n-1

818=n-1

818+1=n

819=n

hence,819 terms have to be considered in order to get a sum of 5740.