Question 240250: The four children in the Dempsey family have a combined age of 25 years. Jennifer’s oldest brother is six times as old as she is. Her next-to-oldest brother is 5 years older than she is, and the youngest of her brothers is twice Jennifer’s age. How old is each of the Dempsey children?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! The four children in the Dempsey family have a combined age of 25 years.
Jennifer’s oldest brother is six times as old as she is.
Her next-to-oldest brother is 5 years older than she is, and the youngest of her brothers is twice Jennifer’s age.
How old is each of the Dempsey children?
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Let the 4 children's ages be, j, a, b, c
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Write an equation for each statement:
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" The four children in the Dempsey family have a combined age of 25 years."
j + a + b + c = 25
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" Jennifer’s oldest brother is six times as old as she is."
a = 6j
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" Her next-to-oldest brother is 5 years older than she is,"
b = j + 5
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" and the youngest of her brothers is twice Jennifer’s age."
c = 2j
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How old is each of the Dempsey children?
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Note that each are in terms of j, so we just substitute
j + a + b + c = 25
j + 6j + (j+5) + 2j = 25
combine like terms
j + 6j + j + 2j + 5 = 25
10j = 25 - 5
10j = 20
j = 
j = 2
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Now you use the equations we have, to find the ages a, b, c.
Check by adding them up and seeing if they equal 25
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