Who can help me???A Maths question.(2)

2007-11-25 5:48 am

A father is now three times as old as his son; in 15 years's thime he will be twice as old as his son. How old is he now?

Please have setps!!

更新1:

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回答 (2)

[匿名]

2007-11-25 6:00 am

let the age of the son be x, thus his father is 3x years old.
2(x+15)=3x+15
2x+30=3x+15
3x-2x=30-15
x=15
age of son=15
age of father=3x15=45
(after 15 years: son's age=30,father's age=60, 60/30=2)

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雞尾包

2007-11-25 5:57 am

son's age now = x
father's age now = 3x
after 15 years,
3x + 15 = 2(x + 15)
3x + 15 = 2x + 30
x = 15
he is 15 now

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