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ValentinaT
Help please? With steps?
How far did you get with this?
Hold on a second please, I'm writing.
Kk. Cause I do have a path to the answer...
\[\frac{ 72 }{ 2 } + \frac{ 72 }{ x } = \frac{ 72 }{ 1.5 }?\]
hmm... I can see where you got the 72/2 and 72/1.5.... but the 72/x makes no sense to me.
Sorry, I was looking at the example in my book, and tried to model it like it.
\(c_1 cpm=\frac{72}{2}\) and \(c_2 cpm=?\) Where cpm is Copies Per Minute \(1.5(c_1 cpm+c_2 cpm)=72\)
Once you know the CPM for the old copier, you can find out how long it takes to make 72 copies.
Sorry, I was writing this down.
Your method might actually do that in one shot, don't know. You could run it both ways and see.
How do I find the cpm for the old copier? \[1.5(\frac{ 72 }{ 2 } + \frac{ 72 }{ x }) = 72\]?
You just need x. Not 72/x.
Okay. \[1.5(\frac{ 72 }{ 2 } + x) = 72\]
Can you give me a hint on what to do next?
Move the 1.5 to the other side, do the dractions. They become nice numbers.
fractions... oops. I was checking the other way. It would get a very bad number.
Okay. \[\frac{ 15 }{ 10 } (\frac{ 72 }{ 2 } + x) = 72\] End up with 12.
My version of the work:\[1.5\left(\frac{ 72 }{ 2 } + x\right) = 72 \\ \implies \frac{ 72 }{ 2 } + x = \frac{72}{1.5} \\ \implies 36 + x = 48 \\ \implies x = 48-36 \\ \implies x = 12\]So 12 copies per minute. Then the time for 72 copies is \(\frac{72}{12}\)
Yah, these and riverboat problems are all about finding what is added and what is multiplied. The true goal of word problems is trying to help you figure out how math works in real life rather than just in homework.
/cheer Yep. Really slow copier.