SOLUTION: Four years ago a woman was three times as old as her sister. in five years time she will be 20 years older than her sister. what is the present age of the woman and her sister?
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Question 624876: Four years ago a woman was three times as old as her sister. in five years time she will be 20 years older than her sister. what is the present age of the woman and her sister?
You can put this solution on YOUR website! let w = present age of the woman
let s = present age of the sister
:
"Four years ago a woman was three times as old as her sister."
w - 4 = 3(s-4)
w - 4 = 3s - 12
w = 3s - 12 + 4
w = 3s - 8
:
"in five years time she will be 20 years older than her sister."
She will always be 20 yrs older than her sister, that is a dumb statement!
Calculated to confuse you
Just say w = s + 20
:
In the 1st equation replace w with (s+20)
s + 20 = 3s - 8
s = 3s - 8 - 20
28 = 3s - s
28 = 2s
s = 28/2
s = 14 yrs is the sisters age
then
14 + 20 = 34 yrs is the woman's age
:
:
Check our solutions in the statement:
"Four years ago a woman was three times as old as her sister."
34 - 4 = 3(14-4); confirms our solution
