Question 1015041: In three years time, Mr. Sullivan will be three times as old is his daughter. Six years ago, he was six times as old as she was. How old are they now?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! let s = Sullivan's age
let d = daughter's age
:
Write an equation for each statement
:
" In three years time, Mr. Sullivan will be three times as old is his daughter."
s + 3 = 3(d + 3)
s + 3 = 3d + 9
s = 3d + 9 - 3
s = 3d + 6
"Six years ago, he was six times as old as she was."
s - 6 = 6(d - 6)
s - 6 = 6d - 36
s = 6d - 36 + 6
s = 6d - 30
How old are they now?
s = s, so we can write it:
6d - 30 = 3d + 6
6d - 3d = 6 + 30
3d = 36
d = 36/3
d = 12 yrs old is the daughter
:
find s using the equation; s = 3d + 6
s = 3(12) + 6
s = 42 yrs is Sullivan's age
:
:
Let's check this in the 2nd statement
" Six years ago, he was six times as old as she was."
42 - 6 = 6(12 -6)
36 = 6(6)
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