If the edge of a cube is 2x, the volume of the cube is ?

$20.16

Step-by-step explanation:

First we need to find 12% of his current hourly rate, 12% is our decimal multiplier here so we use 0.12. In order to get 12% we need to multiply our decimal by $18 which is:

$18 × 0.12 = $2.16

Now let's add this 12% on top of his current hourly rate.

$18 + $2.16 = $20.16

And that's the final answer.