Question

In gym class, sue is shooting basketball free throws. she is shooting three sets of twenty shots each. in her first two attempts, she made 13 and 18 free throws. what are the possible scores on her third attempt if she is to have an average between 12 and 16 free throws after all three attempts? express your answer in the form of a compound inequality using the variable f to represent a successful basketball free throw.

Answer 1

In order to achieve an average of 12 successful shots she has to score 36 times in total. So, she has to score 5 times in the 3rd set. 
13 + 18 + 5 = 36

In order to achieve an average of 16 successful shots she has to score 48 times in total. So, she has to score 17 times in the 3rd set. 
13 + 18 + 17 = 48

Express your answer in the form of a compound inequality using the variable F to represent a successful basketball free throw:
5 <= F <= 17