Answer:
multiply by 5/4
Explanation:
You want to know how to get 12:8:4 to be 15:10:5.
Lowest terms
The common factor in the ratio 12:8:4 is 4, so we can divide by that to reduce it to lowest terms:
12/4 : 8/4 : 4/4 = 3 : 2 : 1
Multiple
To make the first number be 15, we can multiply the ratio by 5:
3(5) : 2(5) : 1(5) = 15 : 10 : 5
Effectively, we have multiplied the original ratio by 5/4.
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