Question 609257: Frank is 4 times as old as Lin. the difference in their ages is equal to Lin's age plus 8. how old is each?
Answer by math-vortex(648)   (Show Source):
You can put this solution on YOUR website! Hi, there--
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Let F be Franks age.
Let L be Lin's age.
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Now write two equations using the information we are given.
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In algebra, "Frank is 4 times as old as Lin," can be written as
F = 4L
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"The difference in their ages is equal to Lin's age plus 8," can be written as
F - L = L + 8
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We use substitution to solve the equations. Substitute 4L for F in the second equation
F - L = L + 8
4L - L = L + 8
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Combine like terms and solve for L.
3L = L + 8
2L = 8
L = 4
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Substitute 4 for L in the first equation.
F = 4L
F = 4*4
F = 16
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Frank is 16 and Lin is 4 years old. Check your answers using the original language of the problem.
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16 is four times as old as 4? Yes!
The difference (16-4=12) is equal to Lin's age plus 8 (4+8=12)? Yes!
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That's it! Feel free to email if you have questions,
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Ms.Figgy
math.in.the.vortex
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