9 men working 8 hours per day dig 30 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 choice from the following: A) 33 B) 66 C) 88 D) 11 E) 281

Rationale: "( 9 * 8 ) / 30 = ( x * 6 ) / 50 = > x = 20 20 – 9 = 11 answer : d"
Answer: D