Answer:
$18.19
Explanation:
First - Convert all the percents into decimals by moving the decimal to the left twice, 15% -> 0.15, 7% -> 0.07
Second - Then, the discount, multiply & subtract , 20 * 0.15 = 3 -> 20 - 3 = 17
Third - Then, the tax, multiply & add, 17 *0.07 = 1.17 -> 17 + 1.17 = 18.19