Answer:
I don't know the last 2 but the 1st 2 are both 25
quantity decrease from 20-15 is 25%
quantity increase to 15-20 is 33.3%
Step-by-step explanation:
a. work: 20-15 = 5
5 / 20 = 0.25 x 100
b. work: 20-15 = 5
5/15 = 0.3333333333333
0.3333333333333 x 100 = 33.33333333333 and round
