GMAT Word Problems Explained — Working at a constant rate, a copy machine makes 20 copies of

Working at a constant rate, a copy machine makes 20 copies of a one-page document per minute. If the machine works at this constant rate, how many hours does it take to make 4,800 copies of a one-page document?

word problemstranslationsconversionsrates

Explanation	Calculations	Help
$We define the variables for the total number of copies and the time in minutes.$	$C = number of copies T = time in minutes$	Theory & Tactics Method Card TRANS1-A Click to view full details
$We translate "a copy machine makes 20 copies of a one-page document per minute" into a rate equation.$	$C = 20 T$	Theory & Tactics Method Card TRANS3-D Click to view full details
$We translate "4,800 copies" as the total number of copies to be produced.$	$C = 4800$	Theory & Tactics Method Card TRANS1-B Click to view full details
$We set up the equation relating copies to time and solve for T .$	$4800 = 20 T T = \frac{4800}{20}$
$We simplify to find the time in minutes.$	$T = 240$
$We convert the time from minutes to hours by dividing by 60.$	$H = \frac{T}{60}$	Theory & Tactics Method Card TRANS4-D Click to view full details
$We calculate the number of hours.$	$H = \frac{240}{60} = 4$

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It takes 4 hours, so the correct answer is A.