Re: Lisa is older than...

The first equation is correct. I think you want $\displaystyle y+5 = 3(x+5) $ for the second equation.

Re: Lisa is older than...

I get the answer -5. How is that correct?

Thank you.

Re: Lisa is older than...

The first equation I am referring to is $\displaystyle y=4x$. To summarize, the equations are $\displaystyle y=4x$ and $\displaystyle y+5=3(x+5)$. So x=10.

Re: Lisa is older than...

Quote:

Originally Posted by

**heaviside** The first equation I am referring to is $\displaystyle y=4x$. To summarize, the equations are $\displaystyle y=4x$ and $\displaystyle y+5=3(x+5)$. So x=10.

Ah, I see. Thank you!

Re: Lisa is older than...

Notice that the question asked "How old are Lisa and Anne". Just answering "x= 10" would NOT be acceptable. You started by saying that "Lisa is four times older than Anne" turned into y= 4x so apparently you are saying that Annes current age is 10 and Lisa's current age is 4(10)= 40.

By the way, **I** would argue that y= 4x would be "Lisa is **four times as old as** Anne". I would interpret "Lisa is four times older than Anne" as meaning that the difference between Anne and Lisa's age is four times Anne's age. That would translate to y- x= 4x or y= 5x.

Re: Lisa is older than...

Quote:

Originally Posted by

**HallsofIvy** Notice that the question asked "How old are Lisa and Anne". Just answering "x= 10" would NOT be acceptable. You started by saying that "Lisa is four times older than Anne" turned into y= 4x so apparently you are saying that Annes current age is 10 and Lisa's current age is 4(10)= 40.

By the way, **I** would argue that y= 4x would be "Lisa is **four times as old as** Anne". I would interpret "Lisa is four times older than Anne" as meaning that the difference between Anne and Lisa's age is four times Anne's age. That would translate to y- x= 4x or y= 5x.

Yea, sorry about the grammatical errors. I am translating the question from my own language :) Thank you.