Three variables

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Three variables

by Marisa » Fri Mar 06, 2009 6:33 am
Pat, Kate, and Mark charged a total of 162 hours to a certain project. If Pat charged twice as much as Kate and one third as much as Mark, how many more hours did Mark charge than Kate.

I can set up the three equations but cannot solve for all variables. Please advise.
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by gabriel16 » Fri Mar 06, 2009 8:21 am
This is what I came up with:

P+K+M=162
P=2K
P=1/3M

Here is the part where you have to come up with your own formulas:

M=3P
K=P/2

Hence:

P+P/2+3P=162

2P+P+6P=324

P=36

Now that we know P we can find M and K:

36=2K

K=18

M=3(36)

M=108

M-K=?

108-18=90

This is what I came up with, but I certainly could be wrong.

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by Marisa » Fri Mar 06, 2009 11:02 am
I totally understand, thanks! Yes, the OA is 90