A) 7
B) 9
C) 12
D) 14
Correct Answer: B
Solution :
Let the required number of binders be\[x\]. Less books, less binders (Direct proportion) More days, less binders (Indirect Proportion) \[\left. \begin{align} & \text{Books}\,\,\,\text{1400:800} \\ & \text{Days}\,\,\,\,\,\text{20:15} \\ \end{align} \right\}\text{:}\,\,\,\text{:}\,\,\,\,\,\text{21:x}\] \[\therefore \]\[1400\times 20\times x=800\times 15\times 21\] \[\Leftrightarrow \]\[x=\left( \frac{800\times 15\times 21}{1400\times 20} \right)=9\]You need to login to perform this action.
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