SOLUTION: Bill is 2 years older than his brother and 5 years younger than his sister. 5 years ago the sum of the ages of Bill and his bbrother was equal to their sister's age then. How old

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Question 835727: Bill is 2 years older than his brother and 5 years younger than his sister. 5 years ago the sum of the ages of Bill and his bbrother was equal to their sister's age then. How old is Bill now
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = Bill's age
Let y = brother's age
let z = sister's age
:
Bill is 2 years older than his brother
x = y + 2
or
y = (x-2)
and 5 years younger than his sister.
x = z - 5
or
z = (x+5)
:
5 years ago the sum of the ages of Bill and his brother was equal to their sister's age then.
(x-5) + (y-5) = (z-5)
x + y = z - 5 + 10
x + y = z + 5
replace y with (x-2); replace z with (x+5)
x + (x-2) = (x+5) + 5
2x = x + 5 + 5 + 2
2x - x = 12
x = 12 is Bill's age
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