question_answer

10 men working 6 hours a day can complete a work in 18 days. How many hours a day must 15 men work to complete the same work in 12 days?

A)  6                      

B)  10

C)  12      

D)         15

Correct Answer: A

Solution :

\[\therefore \]      \[\left. \begin{matrix}    15:10  \\    12:18  \\ \end{matrix} \right\}:\,\,:6:x\] \[\Rightarrow \]   \[15\times 12\times x\] \[\Rightarrow \]   \[10\times 18\times 6\] \[\Rightarrow \] \[x=\frac{10\times 18\times 6}{15\times 12}=6\]