question_answer 17)

                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?

Answer:

                Suppose that x machines would required. We have the following table.                

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.