word problem with three ratios

Question

My friend's dog is about as many days as my friend in weeks, and my friend's dog is as many months as my uncle in years. My friend's dog, my friend and my uncle together are 120 years. Can you tell me my my uncle's age in years?

Answer 1

d + f + u = 120

dog is as many days as friend is in weeks f = 7d

dog is as many months as uncle is in years u = 12d

d +7d + 12d = 120

20d = 120

d = 6 years old for the dog

f = 7d = 42 years old for the friend

u = 12d =72 years old for the uncle