Question

PLEASE HELP! Medals will be rewarded.

Mary can paint a house 3 times faster than Amy can, working alone. If they can paint the house together in 9 hours, how long does it take Mary working alone?

Answer 1

You can find similar problems to yours in
http://www.saab.org/mathdrills/workcompletion.cgi

Answer 2

Thanks. but it doesn't help

Answer 3

\[m=3a\\
\frac{1}{a}+\frac{1}{m}=\frac{
1}{9}
\]
These are the two equations you have to find. If you do a couple of problems on the link I gave you will understand how I came up with the second equation

Answer 4

When you solve them, you get a=12 and m=36

Answer 5

Are you still there?

Answer 6

I see how you got the fraction. But can you show me what to do afterwards step by step?

Answer 7

Do you understand the second equation?

Answer 8

yeah. the fractions are the amounts they can do in an hr

Answer 9

\[m=3a\\
\frac{1}{a}+\frac{1}{m}=\frac{1}{9}\\
\frac{1}{a}+\frac{1}{3a}=\frac{1}{9}\\

\frac{3}{3a}+\frac{1}{3a}=\frac{1}{9}\\
\frac{4}{3a}=\frac{1}{9}\\
36 =3a\\
a=12\\
m= 3a= 3(12)=36

\]

Answer 10

Did you get it?

Answer 11

Are you still there?

Answer 12

frac{3}{3a}+\frac{1}{3a}=\frac{1}{9}

where did you get 3/3a?

Answer 13

\[
\frac 1 a = \frac 3 {3a}
\]
Multiply up and down by 3