• # question_answer 18)                 A factory requires 42 machines to produce a given number of articles in 63 days. How many machines would be required produce the same number of articles in days?

 Number of machines 42 $x$ Number of days 63 54
Lesser the number of machines, more will be the number of days to produce the same number of articles. So, this is a case of inverse proportion. Hence,   $42\times 63=x\times 54$ $\Rightarrow$               $x=\frac{42\times 63}{54}$ $\Rightarrow$               $x=49$ Hence, 49 machines would be required.