Question

If 12 carpenters working 6 hours a day can make 460 chairs in 240 days, the number of chairs made by 18 carpenters in 360 days each working 8 hours a day will be:

• A. $1380$
• B. $1320$
• C. $1260$
• D. $920$

Answer 1

The correct option is A $1380$

$12$ carpenters working $6$ hours a day can make $460$ chairs in $240$ days.

$\Rightarrow$ $12\times 240\times 6$ hours of work can make $460$ chairs.

Let $18$ carpenters working $8$ hours a day can make $n$ chairs in $36$ days.

$\Rightarrow$ $18\times 360\times 8$ hours of work can make $n$ chairs.

Since, number of working hours is directly proportional to the number of chairs that can be made,

$\Rightarrow$ $12\times 240\times 6:18\times 360\times 8=460:n$

$\Rightarrow$ $\frac{12\times 240\times 6}{18\times 360\times 8}=\frac{460}{n}$

$\Rightarrow$ $n=\frac{460\times 18\times 360\times 8}{12\times 240\times 6}$

$\Rightarrow$ $n=1380$