Answer: The required average is $576.
Step-by-step explanation:
Since we have given that
Percent of customers not returning each year = 25%
Average customer lifetime = [tex]\dfrac{1}{0.25}=4\ years[/tex]
Percent of margin on the average bill = 60%
Cost per visit = $12
Number of times each year visited = 20 times
So, Average expense by each customer per year = [tex]12\times 20=\$240[/tex]
Average margin = 60% of 240 = [tex]0.6\times 240=\$144[/tex]
Average non discounted gross profit during a customer's lifetime is given by
[tex]144\times 4=\$576[/tex]
Hence, the required average is $576.