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The ratio of two numbers is 3:5. When 4 is subtracted from the lesser of the two numbers and 8 is added to the larger of the two, the new ratio is 2:7. What is the greater of the two numbers before 8 is added to it? 

 

I decided to make the smaller number x and the larger number y. Here is what I have, x:y = 3:5 and x-4:y+8=2:7.

I do not know what to do after this. CAn someone help explain? I do not want answers. 

 May 13, 2020
 #1
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Let  the smaller  number  =  x  and  the greater  = y

 

We know that

 

x / y   = 3/5     ⇒ x = (3/5)y       (1)

 

And  we know that

 

[ x - 4]              2

______  =     ___

[y + 8]              7

 

Sub (1) into this for  x

 

[ (3/5)y - 4 ]              2

_________  =       ___

 [ y + 8]                   7

 

 

Cross-multiply  and you have

 

7 [ (3/5)y - 4 ]  =  2 [ y + 8]

 

You should be able to solve it now for the larger number, y

 

 

 

cool cool cool

 May 14, 2020
edited by CPhill  May 14, 2020

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