# QA – Placement Quizzes | Work and Wages | Question 11

10 men working 9 hours a day can complete a work in 24 days. How much time will it take to complete the work if 15 men are employed for 6 hours a day?**(A)** 18**(B)** 20**(C)** 24**(D)** 30**Answer:** **(C)****Explanation:** Here, we need to apply the formula **M _{1} D_{1} H_{1} E_{1} / W_{1} = M_{2} D_{2} H_{2} E_{2} / W_{2}**, where

M

_{1}= 10 men

D

_{1}= 24 days

H

_{1}= 9 hours/day

W

_{1}= W

_{2}= Work to be done

E

_{1}= E

_{2}= Efficiency of each man

M

_{2}= 15 men

D

_{2}= Days required by 15 men

H

_{2}= 6 hours/day

So, we have

10 x 24 x 9 = 15 x 6 x D

_{2}

=> D

_{2}= 24

Therefore, 15 men working 6 hours / day would require 24 days to complete the work.

**Note :**Here, 10 men working 9 hours a day is equivalent to 90 working hours by 1 man. 15 men working 6 hours / day is also equivalent to 90 working hours by 1 man. Hence, the number of days required to complete the work would not change.

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