SOLUTION: My daughter is having a tough time with this equation. Fifteen years ago, Alberto was twice as old a Rosa. In nine more years, he will be twice as old as she was when he was a

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Question 129733: My daughter is having a tough time with this equation.
Fifteen years ago, Alberto was twice as old a Rosa. In nine more years, he will be twice as old as she was when he was as old as she is now. How old is Rosa?
Any help is appreciated.
Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
All of these type problems can be solved this way:
Let = Alberto's age now
Let = Rosa's age now
In order to talk about their ages 15 years ago,
you have to subtract 15 from EACH of their ages

The next part is very tricky, and I sort of
take it one or two words at a time
It's about Alberto in 9 more years. That's

He's going to be twice as old as something, so
I've got = 2 x ?
Now I've got the brain-twister
"twice as old as she was when he was as old as she is now."
I can grapple with it better if I put actual numbers on their
ages, just for now.
Say he is 10 and she is 6 now
4 years ago he was 6 like she is now. Call this age

because is her age now, or 6 years old
This is "when he was as old as she is now."
Now how old was she?

This is "as old as she was", or
Now I put it all together

(1)
and from above,

(2)
multiply (2) by and subtract from (1)

Alberto's age now

Rosa's age now
check answers

OK

OK
whew!