In a certain company, the ratio of the number of managers to the number of production - line workers is 5 to 72. If 8 additional production - line workers were to be hired, the ratio of the number of managers to the production - line workers would be 5 to 74. How many managers does the company have ?

A. 10

B. 20

C. 25

D. 30

Answer: Option B

Solution(By Examveda Team)

Let the number of managers and production - line workers be 5x and 72x respectively
Then,
$$\eqalign{ & = \frac{{5x}}{{72x + 8}} = \frac{5}{{74}} \cr & \Rightarrow 370x = 360x + 40 \cr & \Rightarrow 10x = 40 \cr & \Rightarrow x = 4. \cr} $$
∴ Number of managers = 5 × 4 = 20