Question 72347: Jeanne is three times as old as Michel. The sum of their ages is 20 years. Find out their age now. Found 2 solutions by bucky, Earlsdon:Answer by bucky(2189) (Show Source):
You can put this solution on YOUR website! Call Jeanne's age J and call Michael's age M.
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The problem tells you that Jeanne is 3 times Michael's age. In equation form this is:
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J = 3*M
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The problem also tells you that the sum of their ages is 20. In equation form this is:
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J + M = 20
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There are two unknowns and therefore we need two equations to solve for these unknowns.
We have our two equations.
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As a result of our first equation we known that J = 3*M. Therefore, we can substitute
3*M for J in our second equation. When we do that the second equation becomes:
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3*M = M = 20
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Adding the terms on the left side results in:
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4*M = 20
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Dividing both sides of this equation by 4 tells us that:
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M = 5
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So we know that Michael's age is 5. And since Jeanne is 3 times as old as Michael,
then Jeanne must be 15.
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Finally, as a check, you can note that the sum of their ages (5 + 15) is 20, which is
exactly what the problem said it should be.
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Hope this helps you to understand how to translate this word problem into equations,
and then how to solve the equations to get the answer.
You can put this solution on YOUR website! Let J = Jeanne's age and M = Michel's age. From the problem description, you can write:
J = 3M Substitute this into the equation below and solve for M
J + M = 20
3M + M = 20
4M = 20 Divide both sides by 4.
M = 5 This is Michels's age.
J = 3M = 3(5) = 15 This is Jeanne's age.
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