Question 169868
HARRY IS FIVE YEARS OLDER THAN DON. THREE YEARS AGO DON WAS TWO-THIRDS AS OLD AS HARRY. HOW OLD IS HARRY? 
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Let x = Don's age
then from "HARRY IS FIVE YEARS OLDER THAN DON." we have:
x+5 = Harry's age
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Finally, from "THREE YEARS AGO DON WAS TWO-THIRDS AS OLD AS HARRY." we get our equation:  (three years ago means current year minus 3)
x-3 = (2/3)(x+5-3)
x-3 = (2/3)(x+2)
3x-9 = 2(x+2)
3x-9 = 2x+4
x-9 = 4
x = 13 years (Don's age)
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Harry's age:
x+5 = 13+5 = 18 years