Question

一道英文数学提！janet is three times as old as her daughter,mary.five years ago jant was four times

janet is three times as old as her daughter,mary.five years ago jant was four times as old as mary .how old is janet now?how old will mary be in 7 years'time

Answer 1

Suppose Mary is x years old now. Then
4*(x-5) = 3x-5
Solve it, get x = 15
So Janet is 3x = 45 years old now and Mary will be 22 years old in 7 years' time.

Answer 2

if Mary is x years old this year

then, 3x-5=4*(x-5)
3x-5=4x-20
x=15

Janet is 3*15=45 years old.
Mary will be 15+7=22 years old 7 years later.

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