Answered

A father is four times as old as his daughter. In 7 yrs, he will be three times as old as she is. How old is the daughter now?

Sagot :

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