SOLUTION: Lisa will be twice as old as her brother Ralph in 6 years. Lisa was three times as old as Ralph 3 years ago. What are their ages now?

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Question 681038: Lisa will be twice as old as her brother Ralph in 6 years. Lisa was three times as old as Ralph 3 years ago. What are their ages now?
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
Let x=Ralph' age now
And Let y=Lisa's age now
y+6=2(x+6);
y+6=2x+12;
2x-y=-6-----------------eq1
y-3=3(x-3);
y-3=3x-9;
3x-y=6----------------eq2
subtract eq1 from eq2:
x=12-----------Ralph's age now
substitute x=12 in eq2
3*12-y=6
-y=6-36
y=30-----------Lisa's age now
CK
30+6=2(12+6)
36=36
and
30-3=3(12-3)
27=27
Hope this helps----ptaylor