81 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?	Select the correct option.
A) 99	B) 77	C) 66	D) 55	E) 88

Rationale: "( 81 * 8 ) / 30 = ( x * 6 ) / 50 = > x = 180 180 – 81 = 99 answer : a"
Answer: A