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Problem solving - RATIOS

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Problem solving - RATIOS

by Xbond » Sun May 31, 2009 10:17 am
Hi there,

could you help me to resolve this problem ?


The number of stamps that Kaye and Alberto had were in the ration or 5 : 3, respectively. After Kaye gave Alberto 10 of her stamps, the ratio of the number Kaye had to the number Alberto had was 7 : 5. As a result of this gift, Kaye had how many more stamps than Alberto?

(A) 20 (B) 30 (C) 40 (D) 60 (E) 90



I answered D but the right answer is C
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by tdadic84 » Sun May 31, 2009 2:09 pm
i can see you got the answer D..which means you ended up with K has 150 and A has 90 = 60....BUTTTTTTTTT

you forgot to take 10 away from K and give A 10, which would then be K has 140 and A has 100 and a difference of 40...

and hence the answer is C
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Re: Problem solving - RATIOS

by exhilaration » Sun May 31, 2009 2:29 pm
Xbond wrote:Hi there,

could you help me to resolve this problem ?


The number of stamps that Kaye and Alberto had were in the ration or 5 : 3, respectively. After Kaye gave Alberto 10 of her stamps, the ratio of the number Kaye had to the number Alberto had was 7 : 5. As a result of this gift, Kaye had how many more stamps than Alberto?

(A) 20 (B) 30 (C) 40 (D) 60 (E) 90



I answered D but the right answer is C
1) Setup your fractions

5/3 = 7/5

2) Add x for the unknowns to the original fraction to reflect the changes in the stamps

5x-10 / 3x+10

3) Set the old fraction equal to the new fraction

5x-10 / 3x+10 = 7/5

4) Solve for x, to get x = 40

5) Plug x back into the original fraction 5x-10 / 3x+10, you get Kaye = 140 and Alberto = 100. The difference is 40 (C)
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by Xbond » Mon Jun 08, 2009 1:13 pm
Many thks
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