The work done by a women in 8 hours is equal to the work done by a man in 6 hours and by a boy in 12 hours. If working 6 hours per day 9 men can complete a work in 6 days, then in how many days can 12 men, 12 women and 12 boys together finish the same work, working 8 hours per day ?
A. $${\text{1}}\frac{1}{2}{\text{ days}}$$
B. $${\text{3 days}}$$
C. $${\text{3}}\frac{2}{3}{\text{ days}}$$
D. $${\text{4}}\frac{1}{2}{\text{ days}}$$
Answer: Option A
Solution(By Examveda Team)
Ratio of time taken by a woman, a man and a boy$$\eqalign{ & = 8:6:12 \cr & = 4:3:6 \cr} $$
So, 4 women ≡ 3 men ≡ 6 boy
(12 mens + 12 womens + 12 boys)
$$\eqalign{ & = \left[ {12 + \left( {\frac{3}{4} \times 12} \right) + \left( {\frac{3}{6} \times 12} \right)} \right]{\text{men}} \cr & {\text{ = }}\left( {12 + 9 + 6} \right){\text{men}} \cr & = 27{\text{ men}} \cr} $$
Let the required number of days be x
More men, Less days (Indirect proportion)
More working hours, Less days (Indirect proportion)
\[\left. \begin{gathered} {\text{Working hours 8}}:6 \hfill \\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{Men 27}}:9 \hfill \\ \end{gathered} \right\}::6:x\]
$$\eqalign{ & \therefore \,27 \times 8 \times x = 9 \times 6 \times 6 \cr & \Leftrightarrow x = \frac{{\left( {9 \times 6 \times 6} \right)}}{{\left( {27 \times 8} \right)}} \cr & \Leftrightarrow x = \frac{3}{2} \cr & \Leftrightarrow x = 1\frac{1}{2} \cr} $$
Related Questions on Chain Rule
A. Rs. $$ {\frac{{{\text{xy}}}}{{\text{d}}}} $$
B. $${\text{Rs}}{\text{.}} {xd} $$
C. $${\text{Rs}}{\text{.}} {yd} $$
D. Rs. $$ {\frac{{{\text{yd}}}}{{\text{x}}}} $$
A. $$29\frac{1}{5}$$
B. $$37\frac{1}{4}$$
C. 42
D. 54
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