Question 401587: Ann's age is seven-tenths of Bill's age. In 4 years Ann's age will be eight-elevenths of Bill's age. How old is Bill now? Found 2 solutions by stanbon, josmiceli:Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Ann's age is seven-tenths of Bill's age. In 4 years Ann's age will be eight-elevenths of Bill's age. How old is Bill now?
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Equations:
a = 0.7b
(a+4) = (8/11)(b+4)
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Substitute for a and solve for "b":
(7/10)b+4) = (8/11)b + (32/11)
Multiply thru by 110:
77b + 440 = 80b + 320
3b = 120
b = 40
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Solve for "a":
a = (7/10)b
a = (7/10)40
a = 28
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Cheers,
Stan H.
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You can put this solution on YOUR website! Let = Ann's age now
Let = Bill's age now = Ann's age in 4 years = Bill's age in 4 years
given:
(1)
(2)
--------------------------------
(1)
and,
(2)
Multiply both sides by
(2)
Substitute (1) into (2)
(2)
(2)
(2)
(2)
Bill is 40 now
check answer:
From (1),
(1)
(1)
And, frm (2),
(2)
(2)
(2)
OK
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