Question

The sum of first four term of an Ap is 40 the ratio of product of first and fourth term to second and third term is 2:3
Find those term

Answer 1

Answer:4,8,12,16,20

Step-by-step explanation:

4/2(2a+(4-1)d)=40

2a+3d=20-(1)

a(a+3d)/(a+d)(a+2d)=2/3

3(a^2+3ad)=2(a^2+3ad+2d^2)

3a^2+9ad=2a^2+6ad+4d^2

a^2+3ad-4d^2=0

a^2+4ad-ad-4d^2=0

a(a+4d)-d(a+4d)=0

(a+4d)(a-d)=0

a=-4d a=d

put in (1)

2a+3d=20

2d+3d=20

5d=20

d=4

a=d=4

sequence is 4,8,12,16