Jeremy is paid $18 and an 18% tip for every haircut he gives.
How much does he make if he
gives one haircut?

$21.24

Explanation:

       This means that Jemery is paid the original cost and the tip added together. The original is 100%, so we will do the following:

100% + 18% = 118%

       To answer the question, we will find 118% of $18. A percent divided by 100 becomes a decimal.

118% / 100 = 1.18

$18 * 1.18 = $21.24

      He will make $21.24 for one haircut.

$21.24

Explanation:

He is paid $18 and an 18% tip for each haircut

So amount paid for haircut = $18

And amount paid in tip = 18% of 18 = $3.24

So total amount paid for 1 haircut = $18 + $3.24 = $21.24

the answer would be the third option, "no, ariel should have added 9^2 and 12^2 and compared that to 15^2."

this is found through the pythagorean theorem, which is a^2 + b^2 = c^2.

this is the correct way of solving the problem:

9^2 + 12^2 = 15^2

81 + 144 = 225

225 = 225