# Need help with CWP3 SM

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I need help solving this SM way so I can explain to my DS. I can do it my way, but I can't figure out how to diagram this SM way.

Here it is:

Four rock-climbers have a length of rope each. Arthur and Bobby have 52 yr of rope altogether. Arthur and Dennis have 47 yr of rope in total. Dennis and Fred have a total of 62 yr of rope. What is the total length of rope Bobby and Fred have?

Anybody????!

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Oh gosh, I think I remember this one. I had to sit and work it out myself before I could guide Rebecca through it. I used a bar diagram (and that technique is new to me too). Ummmm, hopefully someone else will come along and explain it?

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I had my son do it :)

We're in 5 now. He said, "I don't remember this one."

Key is first and third facts.

He drew four bars, but didn't worry about lengths... A + B is 52 ...so he has A bar, B bar, and 52 as their sum to the right.

D+F is 62, so he's got those two bars with a 62 as their sum to the right.

There isn't any overlap, so the sum of all 4 rope lengths is 114.

We know that A+D is 47. Subtracting 47 from the total length gives B+F as 67 yds.

My husband looked at the work as I had my son explain it and said, "that's easier than how I'd have done it!" :)

I like Singapore!

HTH.

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Yeah. I could do a nifty but long winded method of solving three simultaneous equations (well I could in 1995) but that is easier.

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I had my son do it :)

We're in 5 now. He said, "I don't remember this one."

Key is first and third facts.

He drew four bars, but didn't worry about lengths... A + B is 52 ...so he has A bar, B bar, and 52 as their sum to the right.

D+F is 62, so he's got those two bars with a 62 as their sum to the right.

There isn't any overlap, so the sum of all 4 rope lengths is 114.

We know that A+D is 47. Subtracting 47 from the total length gives B+F as 67 yds.

My husband looked at the work as I had my son explain it and said, "that's easier than how I'd have done it!" :)

I like Singapore!

HTH.

I GOT IT!

I think i am going to color code on the diagram each person so he can "see" the solution. We are having a complete mental block.

Thanks so much.

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