Answer: 16
its just x plus 1/3 of x. This is harder to find so youre probably not expected to find it this way.
Actual way to solve it.
set up proportion.
=
cross multiply
3 x x = 3x
12 x 4 = 48
48 = 3x
divide by 3 to get x
48 / 3 = 16
x = 16
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