John’s age is three times that of alan’s. ralph’s age is twice that of alan’s.

what is the ratio of john’s age to ralph’s?

So an easy way is to pig in a number for Alan's age to figure out the ratio. 
so let's say Alan is 9 so 9*3 would be John's age, so John is 27. 
9*2 would be Ralph's age would be 18 so now you can make a fraction or the ratio since it is John/ (to) Ralph it would be John over Ralph 
so it's 27/18 now you can reduce this fraction. so divide both numbers by 9 
the new and reduced fraction is 3/2 or 3:2 that is your ratio hope this helped you have an amazing rest of the day!!!