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!!!