One copy machine can make 30 copies a minute, and a second copy machine makes 20 copies a minute. If the two copiers work together, how long would it take them to make 2,000 copies?  Choose the correct answer:
A) 20 minutes
B) 40 minutes
C) 45 minutes
D) 50 minutes
E) 55 minutes
Total work done by both machines in a minute = 30 + 20= 
<gadget id="calculator">30 + 20</gadget>
<output>50</output>
50 copies   Total number of copies required= 2000   Time = 2000/50= 
<gadget id="calculator">2000/50</gadget>
<output>40</output>
40 mins   Answer 40 minutes
<result>B</result>
One copy machine can make 30 copies a minute, and a second copy machine makes 20 copies a minute. If the two copiers work together, how long would it take them to make 2,000 copies?