Answer the following question, with explanation first.
John is twice as old as Mary and half as old as Tonya. If Tanya is 60, what is their average age?

35
John is 30 because 60 / 2 = 30.

Mary is fifteen because 30 / 2 = 15.

Their total age is 105 because 60 + 30 + 15 = 105.

Their average age is 35 because 105 / 3 = 35.

.

The final answer: 35