If 18 bindres bind 900 books in 10 days , How many binders will be required to bind 660 books in 12 days?
Choose the correct choice from the following options
A) 17
B) 77
C) 12
D) 11
E) 91
Explanation:   Let the required no of binders be X.   Less books , Less binders (11irect Proportion)   More days, Less binders (Indirect proportion)   \inline \fn_jvn \left.\begin{matrix} Books\: 900:600\\ 11ays\: \: 12:10 \end{matrix}\right\}::18:x   \inline \fn_jvn \therefore \inline \fn_jvn (900\times 12\times x)=(600\times 10\times 18) \inline \fn_jvn \Leftrightarrow x= \inline \fn_jvn \frac{600\times 10\times 18}{900\times 12} = 11   Answer: 11
<result>D</result>
If 18 bindres bind 900 books in 10 days , How many binders will be required to bind 660 books in 12 days?