We can use a variable equation to solve this. Let A represent alan's age, B represent bob's age, and C represent Cindy's age. So Bob's age would be Alan's age - 5, or a -5 = B. Then Bob's age would be double Cindy's age, so that means 2 multiplied by Cindy's age = Bob's age, or 2C = B. Your two equations are:
A - 5 = B 2C = B
Also a third equation that helps is A + B + C = 20.
Finally, here are the ages. Alan = 11 years old Bob = 6 years old Cindy = 3 years old.
PS: Sorry, I'm not that good at explaining things, but here are the answers
