Simplifying a ratio: How does it get 63 to 147 = 3:7?

jmasta

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Nov 2, 2016
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11
I am stuck on this process. I worked out the first portion of the problem, and I got help my my math lab, but it doesn't tell me how it got to the answer. So, it says the ratio of boys to girls is 63 to 147, or 3:7. How does it get 63 to 147 = 3:7? I have tried division, multiplication and I never seem to get to 3:7.
 

Dr.Peterson

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Nov 12, 2017
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Simplifying a ratio works the same way as simplifying a fraction.

If you had the fraction 63/147, you would look for common factors to divide by. You might first try 3, and find that 63÷3 = 21 and 147÷3 = 49, so the fraction is equal to 21/49. Then you might realize that both of these numbers can be divided by 7, so you find that 21÷7 = 3 and 49÷7 = 7, resulting in the fraction 3/7.

Or, if you're insightful, you might just think of dividing by 21 all at once, rather than 3 and then 7. The result is that 63:147 = (63÷21):(147÷21) = 3:7.
 

MarkFL

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Nov 24, 2012
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Divide both numbers by 21. :)
 
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