45 men working 8 hours per day dig 40 m deep. How many extra men should be put to dig to a depth of 50 m working 6 hours per day?  Choose the correct option.
A) 10
B) 20
C) 30
D) 40
E) 50

Rationale: "( 45 * 8 ) / 40 = ( x * 6 ) / 50 = > x = 75 75 – 45 = 30 answer : c"
Answer: C