The answer is 20
the scale factor is 1.25 (to find that out do 12.5/10) then multiply 16 by 1.25 and you get 20.
Here is the equation:

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You need to get "x" by itself so minus 3 from each side

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Divide 8 by 2

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x=4
So each 4 is equivalent to 4
Lets check:

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So that means that Marcus practiced the piano for 4 hours and Donnel practiced for 7
Answer:
C. Add the equations
Step-by-step explanation:
Adding both the equations will help eliminating 5y.