Answer:
0.9
Explanation:
The formula to compute the four-firm concentration ratio is shown below:
= (Total firm sales of industry A) ÷ (Total firm sales of industry B)
where,
Total firm sales of industry A = $5 million + $2 million + $1 million + $1 million
= $9 million
And, the total firm sales of industry B would be
= $2.5 million × 4 firms
= $10 million
So, the ratio would be
= $9 million ÷ $10 million
= 0.9