If 4 men working 10 hours a day earn Rs. 600 per week, then 9 men working 6 hours a day will earn how much per week? Choose the correct choice from the following answers
A) rs 840
B) rs 320
C) rs 810
D) rs 680
E) none of these

Rationale: "explanation : ( men 4 : 9 ) : ( hrs / day 10 : 6 ) : : 600 : x hence 4 * 10 * x = 9 * 6 * 600 or x = 9 * 6 * 600 / 4 * 10 = 810 answer : c"
Answer: C