Answer:
Sale price of a sweat shirt is $15.30 and a soccer ball is $21.08.
Step-by-step explanation:
A). Usual price of a sweat shirt is = $18
Sale price of the sweat-shirt is 85% of the usual price.
Therefore, Sale price = 85% of $18
= 
= $15.30
B). Usual price of a soccer ball is = $24.80
Sale price of the soccer ball is 85% of its usual price.
Therefore, Sale price = 85% of $24.80
= 
= $21.08
Therefore, sale price of a sweat shirt is $15.30 and a soccer ball is $21.08.