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# Can you help me of how to do this question, thanks ;)

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If 2,1/3 : 4,1/3 then 7:__

May 11, 2015

#1
+13

$$2\frac{1}{3} \text{ is to }4\frac{1}{3}\text{ as }7 \text{ is to x}\\\\ \text{Multiply the first two numbers by 3 to get}\\\\ 7 \text{ is to } 13 \text{ as } 7 \text{ is to x}\\\\ \text{So it's now clear what x is!}$$

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May 11, 2015

#1
+13

$$2\frac{1}{3} \text{ is to }4\frac{1}{3}\text{ as }7 \text{ is to x}\\\\ \text{Multiply the first two numbers by 3 to get}\\\\ 7 \text{ is to } 13 \text{ as } 7 \text{ is to x}\\\\ \text{So it's now clear what x is!}$$

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Alan May 11, 2015
#2
+5

sorry but can you show me in more depth I still don't get it

May 11, 2015
#3
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Turn 2 1/3 into an improper fraction.  It becomes 7/3.

Turn 4 1/3 into an improper fraction.  It becomes 13/3.

The ratio of the two numbers is (2 1/3) divided by (4 1/3).  This ratio is the same if we multiply top and bottom by 3, to get 3*(2 1/3) divided by 3*(4 1/3).

This is 3*(7/3) divided by 3*(13/3).

The 3's cancel on the top, leaving 7,  and they cancel on the bottom, leaving 13. So the ratio is 7/13.

The missing number at the start is therefore 13.

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May 11, 2015
#4
+5

Thank you!

May 11, 2015