Question

find the first 5 terms of an AP in which sum of first 5 terms is 12 and half and ratio between first and last term.is 2:3.

Answer 1

S5=n\2(a+l)

125/2=5/2(a+l)

125/5=a+l

(25=a+l)*2

50=2a+2l. ............(1)

a/l=2/3

3a=2l

3a-2l=0. .............(2)

Solving equations (1) and (2) we get

2a+2l-50+3a-2l=0

5a=50

a=10

putting values in equation 2

-2l=-30

l=15

hope it helps.. please mark brainliest