Three years from now, Tully will be twice as old as Kate. How old was Tully a year ago if Kate is now 29 years old?
Three years from now, Kate will be 29 years + 3 years = <T>add(29, 3)=32 years old.
So by that time, Tully will be 32 years x 2 = <T>multiply(32, 2)=64 years old.
This means, Tully is 64 years - 3 years = <T>subtract(64, 3)=61 years old now.
Therefore, Tully was 61 years - 1 year = 60 years old last year.
