SOLUTION: a father seven years ago was eleven times as old as his daughter. now he is four times as old as she is. how old is he? the answer is 40 i just don't know how to acquire it.
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Question 216705: a father seven years ago was eleven times as old as his daughter. now he is four times as old as she is. how old is he? the answer is 40 i just don't know how to acquire it. Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! Let f = father's present age
let d = daughter's present age
:
Write an equation for each statement:
:
"father seven years ago was eleven times as old as his daughter."
f - 7 = 11(d - 7)
f - 7 = 11d - 77
f = 11d - 77 + 7
f = 11d - 70
:
"now he is four times as old as she is."
f = 4d
:
how old is he?
;
Replace f with 4d in the equation: f = 11d - 70
4d = 11d - 70
70 = 11d - 4d
70 = 7d
d = 10 yrs is daughter
then
4(10) = 40 is father
