Question

the sum of 5th and 9th terms of an ap is 72 cm and the sum of 7th and 12th terms is 97. find the a.p

Answer 1

an=a+(n-1)d

Therefore

a+4d+a+8d=72

2a+12d=72----1

a+6d+a+11d=97

2a+17d=97----2

Solving 1 and 2

5d=25

d=5

2a+12(5)=72

2a=72-60

a=6