Answer:
There are 12 white rats in the cage.
Explanation:
3 : 4 The question says there are 16 rats in the cage. Meaning that 16 is the
x4 x4 total. Since 4(from the ratio)x4 is 16. You would multiply 4 on both sides. 
12 : 16 
Meaning there are 12 white rats to 16 total rats. 
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