
Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion 
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September 25th, 2018, 09:47 PM  #1 
Banned Camp Joined: Sep 2018 From: tytyt Posts: 32 Thanks: 0  How to solve this
Hello If the ratio of chocolates to icecream cones in a box is 5:8 and the number of chocolates is 30, find the number of icecream cones. Last edited by skipjack; June 25th, 2019 at 03:52 PM. 
September 25th, 2018, 10:43 PM  #2 
Senior Member Joined: Sep 2015 From: USA Posts: 2,530 Thanks: 1390 
what is your problem?

September 25th, 2018, 11:12 PM  #3 
Banned Camp Joined: Sep 2018 From: tytyt Posts: 32 Thanks: 0 
Hello The chocolates to icecream cones ratio is 5:8=chocolates:icecream cones 5/8=30/icecream cones icecream cones = 30*8/5 icecream cones = 240/5 icecream cones will be 48; is this right/correct? Last edited by skipjack; June 25th, 2019 at 03:54 PM. 
September 26th, 2018, 06:50 AM  #4 
Global Moderator Joined: Dec 2006 Posts: 20,926 Thanks: 2205 
Yes.

June 25th, 2019, 03:37 PM  #5 
Newbie Joined: Jun 2019 From: New York Posts: 23 Thanks: 0 
Hello I got 48 as well. By placing 5/30= 8/x, cross multiplying it will be 5x=240.Then x= 240/5, which is equal to 48. 48 Ice cream cones to 30 chocolates. I saw these 2 links, that was helpful for me in solving this problem: 1) https://mathbitsnotebook.com/Geometr...y/SMRatio.html 2) Hope this helps, I agree with you it is 48. 
June 25th, 2019, 07:12 PM  #6 
Senior Member Joined: Jan 2014 From: The backwoods of Northern Ontario Posts: 391 Thanks: 70 
5:8 = 30:C Here's the way I taught my elementary pupils to solve it when I was a teacher: What do you have to multiply 5 by in order to get 30? Yes, 6 is correct. Then you also have to multiply 8 by 6 as well. That will give you the value of C. 
June 27th, 2019, 11:40 AM  #7  
Member Joined: Jun 2019 From: AZ, Seattle, San Diego Posts: 30 Thanks: 23  Quote:
That's how I learned it (before algebra). The teacher described that method as "multiply on the diagonal and divide by the number not used". $$\dfrac{5}{8} = \dfrac{30}{x}$$ The numbers 8 and 30 lie on the diagonal, so we multiply them. The number not used is 5, so we divide 8×30 by 5, just like you did. This method works whenever you know three out of the four numbers in a proportion. Here are some symbolic examples: $$\dfrac{A}{B} = \dfrac{C}{D}$$ If we know numbers {A,C,D}, then we get B by multiplying on the diagonal and dividing by the number not used. A & D lie on the diagonal, so C is the number not used: B = (A×D)/C If we know {B,C,D}, then we get A = (B×C)/D If we know {A,B,D}, then we get C = (A×D)/B If we know {A,B,C}, then we get D = (B×C)/A That last example is what you did above. Cheers!  

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