Roadrunner Posted March 28, 2013 Share Posted March 28, 2013 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? Quote Link to comment Share on other sites More sharing options...
Roadrunner Posted March 28, 2013 Author Share Posted March 28, 2013 Anybody????! Quote Link to comment Share on other sites More sharing options...
Mommy22alyns Posted March 28, 2013 Share Posted March 28, 2013 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? Quote Link to comment Share on other sites More sharing options...
Dana Posted March 28, 2013 Share Posted March 28, 2013 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. Quote Link to comment Share on other sites More sharing options...
kiwik Posted March 28, 2013 Share Posted March 28, 2013 Yeah. I could do a nifty but long winded method of solving three simultaneous equations (well I could in 1995) but that is easier. Quote Link to comment Share on other sites More sharing options...
Roadrunner Posted March 29, 2013 Author Share Posted March 29, 2013 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. Quote Link to comment Share on other sites More sharing options...
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