Answers

2014-08-24T14:27:24+08:00
Let's make the daughter's age X
so the father's age is 4X
in seven years both of their ages are now seven years more so
Father = 4X + 7 Daughter = X + 7
And the father is now three times older than his daughter so
4X + 7 = 3 (X + 7)
then
4X + 7 = 3X + 21
subtract 7 and 3 x from both sides and you get
4X - 3X = 21 - 7
so
X equals 14
the daughter is 14


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