Answer:
$18
Explanation:
To work out 15% using a calculator:
0.15 multiplied by 120 which is 18
To work out 15% without a calculator:
10% of 120 is 12. (Just remove the last number whenever you want to get 10% or add it on as a decimal if it's greater than 0. e.g. 10% of 40 is 4 but 10% of 48 is 4.8)
To add the 5% divide 12 by 2 which is 6.
Add the 10% to the 5% to get the 15%.
12+6=18