A factory required 42 machines to produce a given number of articles in 56 days. How many machines would be required to produce the same number of articles in 48 days?
More the number of machines, lesser the days required to produce a given number of articles. So, it is an inverse proportion.
Let the required no. of machines be x.
⇒ 42 × 56 = 48 × x
⇒ x = 
= 49 machines
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