Question 1177532

a+d , a+3d , a+7d

(a+3d)/(a+d) = (a+7d)/(a+3d)

(a+3d)^2 = (a+d)(a+7d)

a^2 +6ad +9d^2 = a^2+7ad +ad +7d^2

2ad-2d^2 =0

2d(a-d)=0

a=d.

a+10d =22
a=d
11d=22
d=2, a=2

Ratio 
(a+7d)/(a+3d)= 16/8 =2