5 persons can prepare an admission list in 8 days working 7 hours a day. If 2 persons join them so as to complete the work in 4 days, they need to work per day for ?
A. 8 hours
B. 9 hours
C. 10 hours
D. 12 hours
Answer: Option C
Solution(By Examveda Team)
Let the number of working hours per day be xMore persons, Less working hours ( Indirect proportion)
Less days, More working hours (Indirect proportion)
\[\left. \begin{gathered} {\text{Persons 7}}:5 \hfill \\ {\text{Quantity 4}}:8 \hfill \\ \end{gathered} \right\}::7:x\]
$$\eqalign{ & \therefore {\text{ }}7 \times 4 \times x = 5 \times 8 \times 7 \cr & \Leftrightarrow x = \frac{{\left( {5 \times 8 \times 7} \right)}}{{\left( {7 \times 4} \right)}} \cr & \Leftrightarrow x = 10 \cr} $$
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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
How to comes persons value is 7 : 5