Suppose that the distribution of sales within an industry is as shown in the table.
Firm Share of Total Market Sales
A 25
B 20
C 15
D 14
E 8
F 6
G 5
H 5
I 2
Total 100%
a) What is the four-firm concentration ratio for this industry? ___74%_
b) What is the eight-firm concentration ratio for this industry? _____98%