If 4 men working 10 hours a day earn Rs. 800 per week, then 9 men working 6 hours a day will earn how much per week?  Choose the correct choice.
A) Rs 840
B) Rs 1320
C) Rs 1080
D) Rs 1680
E) None of these
Explanation :   (Men 4:9) : (Hrs/Day 10:6) :: 800 : x   hence 4 * 10 *x = 9 * 6 * 800   or x = 9*6*800/ 4*10 = 1080   Answer : Rs 1080
<result>C</result>
If 4 men working 10 hours a day earn Rs. 800 per week, then 9 men working 6 hours a day will earn how much per week?