A pair of desiner sneakers was bought for $120. Since they were bought their price had increased by 15%. What is the new price

The base price is $120. 15% in decimal form is 0.15, to get 15% of 120 you multiply the decimal form of 15% by 120.

0.15 * 120 = 18

Since the price increased by 15 percent, and $18 is 15% of 120, we add 18 to 120, so the answer is

$138