question_answer

5 person can prepare an admission list in 8 days working 7 h a day. If 2 person join them so as to complete the work in 4 days, they need to work per hour

A)  10 h                

B)  9 h 

C)  12 h    

D)  8 h

Correct Answer: A

Solution :

\[\Rightarrow \left. \begin{align}   & 7:5 \\  & 4:8 \\ \end{align} \right\}::7:x\] \[\therefore \]\[x=\frac{5\times 8\times 7}{7\times 4}=10\,\,h\]