Question 201310
The sum of Richard's age and Ruel's age is 60. Nine years ago, Richard was twice as old as Ruel, then how old is Ruel?
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Let x = Ruel's age
and y = Richard's age
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From:"The sum of Richard's age and Ruel's age is 60." we get:
x + y = 60 (equation 1)
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From:"Nine years ago, Richard was twice as old as Ruel" we get:
y-9 = 2(x-9)  (equation 2)
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Solve equation 1 for y:
x + y = 60
y = 60 - x
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Substitute the above back into equation 2 and solve for x:
y-9 = 2(x-9)
60-x -9 = 2(x-9)
51-x = 2x-18
51 = 3x-18
69 = 3x
23 years = x (Ruel's age)