mama25angels Posted May 1, 2012 Share Posted May 1, 2012 Find a number such that 2/3 of the number is 20 more than 1/4 of the number. Thanks to anyone who can help! Quote Link to comment Share on other sites More sharing options...
Dinsfamily Posted May 1, 2012 Share Posted May 1, 2012 The difference of 2/3 and 1/4 some number needs to equal 20. 2/3-1/4=5/12 So 5/12 of the number is 20 20 is 5/12 of 48 Checking work: 2/3 of 48 is 32, 1/4 of 48 is 12. 32-12=20 so 48 is correct. Hope that helps. Quote Link to comment Share on other sites More sharing options...
mama25angels Posted May 1, 2012 Author Share Posted May 1, 2012 (edited) YES! Thank you so much! Care to try another one? If you take 8/5 of a number and decrease that by 50, you get 4/5 of the number. What is the number? Nevermind, we got!!! Thank you so much for helping with that first one, it really gave us a confidence boost to work on the others!!!! Edited May 1, 2012 by mama25angels Quote Link to comment Share on other sites More sharing options...
Gailmegan Posted May 1, 2012 Share Posted May 1, 2012 50. 8/5-4/5 = 4/5 Quote Link to comment Share on other sites More sharing options...
Gailmegan Posted May 1, 2012 Share Posted May 1, 2012 Looks like you edited while I was posting. I'm glad you figured it out. Quote Link to comment Share on other sites More sharing options...
morosophe Posted May 1, 2012 Share Posted May 1, 2012 Or here's my much longer version of the already-worked problem. Just in case someone likes to see steps. :p (I actually did this on my notepad, just for fun, and before seeing the answer given above.) 2/3 is 20 more 1/4 2/3 = 8/12; 1/4 = 3/12 So, 2/3-1/4 = 5/12 5/12 of the total is 20 5/12x = 20 5x = 20*12 = 240 x = 240/5 = 48 (As you can see, I wasn't even using a calculator.) To prove it: 2/3 of 48 is 32 1/4 of 48 is 12 2/3 is 20 more than 1/4 Quote Link to comment Share on other sites More sharing options...
jetted4 Posted May 1, 2012 Share Posted May 1, 2012 Videotext Algebra Module A teaches how to translate English sentences to math sentences in a way that makes sense to me...can't remember all of it but basically you step through the sentence and look for key words. << 2/3 of the number is 20 more than 1/4 of the number>> in this sentence: 'of' means multiplication, 'is' means equals, 'more than' means addition, 'the number' is your unknown (usually X) so you get 2/3 * X = 1/4 * X + 20 Quote Link to comment Share on other sites More sharing options...
Dinsfamily Posted May 1, 2012 Share Posted May 1, 2012 YES! Thank you so much! Care to try another one? If you take 8/5 of a number and decrease that by 50, you get 4/5 of the number. What is the number? Nevermind, we got!!! Thank you so much for helping with that first one, it really gave us a confidence boost to work on the others!!!! You're welcome. It looks like a Sngapore IP problem :D Quote Link to comment Share on other sites More sharing options...
Dinsfamily Posted May 1, 2012 Share Posted May 1, 2012 (edited) Or here's my much longer version of the already-worked problem. Just in case someone likes to see steps. :p (I actually did this on my notepad, just for fun, and before seeing the answer given above.) 2/3 is 20 more 1/4 2/3 = 8/12; 1/4 = 3/12 So, 2/3-1/4 = 5/12 5/12 of the total is 20 5/12x = 20 5x = 20*12 = 240 x = 240/5 = 48 (As you can see, I wasn't even using a calculator.) To prove it: 2/3 of 48 is 32 1/4 of 48 is 12 2/3 is 20 more than 1/4 Yep, that's exactly what I did except I tend not to set problems like that up in algebraic form. It looks like a Singapore IP problem and the kiddo would be expected to solve it without algebra. Same thing but without the x. After 3 years of CWP, my brain is starting to catch on. I'm an algebra/calculus tutor so that's a big thing for me. Edited May 1, 2012 by Dinsfamily Fixing quote Quote Link to comment Share on other sites More sharing options...
Riverland Posted May 2, 2012 Share Posted May 2, 2012 << 2/3 of the number is 20 more than 1/4 of the number>> in this sentence: 'of' means multiplication, 'is' means equals, 'more than' means addition, 'the number' is your unknown (usually X) so you get 2/3 * X = 1/4 * X + 20 This is how I solve these types of problems. Quote Link to comment Share on other sites More sharing options...
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