Explanation:
a)
8÷2=4
12÷3=4
27÷9=3
•it does'nt always take the same amount of time to serve each customer .
•10×3=30
b)
according to the question
2=18 point
4=36 point
8=72 point
18=9×2
36=9×4
72=9×8
so 1dollar =9point
•each dollar spent appears to earn the same number of point
•because 81=9×9, it costs 9 dollar