SOLUTION: John is four times as old as Harry. In six years, John will be twice as old as Harry. What are their ages now?

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Question 189616: John is four times as old as Harry. In six years, John will be twice as old as Harry. What are their ages now?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Let J = John's present age and H = Harry's present age.
From the problem description, you can write...
1) J = 4H "John is four times as old as Harry" and...
2) J+6 = 2(H+6) "In six years, John will be twice as old as Harry (will be in six years)"
Substitute the J = 4H from equation 1) into equation 2) and solve for H.
2a) (4h)+6 = 2(H+6) Simplify.
2a) 4H+6 = 2H+12 Subtract 2H from both sides.
2a) 2H+6 = 12 Subtract 6 from both sides.
2a) 2H = 6 Finally, divide both sides by 2.
2a) H = 3 and...
1) J = 4(3) = 12
John is 12 years old and Harry is 3 years old.