39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work?
A. 10
B. 13
C. 14
D. 15
Answer: Option B
Solution(By Examveda Team)
Let the required number of days bex.Less persons, More days (Indirect Proportion)
More working hours per day, Less days (Indirect Proportion)
\[\left. \begin{gathered} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{Persons }}\,30:39 \hfill \\ {\text{Working hour/day }}\,{\text{6}}:{\text{5}} \hfill \\ \end{gathered} \right\}::12:x\]
$$\eqalign{ & \therefore 30 \times 6 \times x = 39 \times 5 \times 12 \cr & \Rightarrow x = \frac{{ {39 \times 5 \times 12} }}{{ {30 \times 6} }} \cr & \Rightarrow x = 13 \cr} $$
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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