SOLUTION: Please help me solve this problem: John is as twice as old as Mary today. Three years ago, he was 6 years older than Mary. How old was John four years ago? Thank you..

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Question 584658: Please help me solve this problem:
John is as twice as old as Mary today. Three years ago, he was 6 years older than Mary. How old was John four years ago?
Thank you..
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
John is as twice as old as Mary today. Three years ago, he was 6 years older than Mary.
How old was John four years ago?
:
Let j = J's present age
Let m = M's present age
:
Write an equation for each statement:
:
"John is as twice as old as Mary today."
j = 2m
:
Three years ago, he was 6 years older than Mary.
then he is 6 yrs older than Mary forever
j = m+6
:
2m = m + 6
2m - m = 6
m = 6 yrs is M's age
and
2(6) = 12 yrs is J's age
:
" How old was John four years ago?
12 - 4 - 8 yrs old