Question 1160803: James is 3 times as old as Joy. Three years ago, he is four times as old as Joy. Find the sum of their ages. Found 2 solutions by math_helper, ikleyn:Answer by math_helper(2461) (Show Source):
J = James' age
Y = Joy's age
J = 3Y (1) from "James is 3 times as old as Joy."
J-3 = 4(Y-3) (2) from "Three years ago, he was four times as old as Joy."
Substitute 3Y from (1) for J in (2):
3Y-3 = 4(Y-3)
3Y-3 = 4Y-12
Y = 9 ==> J = 27
Ans: Joy is 9, James is 27
Check: James should be 3*Joy's age: 27 = 3*9 (ok)
and three years ago he should have been 4*Joy's age: 27-3 = 24, which is 4*6, and Joy was 9-3=6 (ok)
