One copy machine can make 15 copies a minute, and a second copy machine makes 10 copies a minute. If the two copiers work together, how long would it take them to make 1,000 copies? Choose the correct choice from the following answers.
A) 20 minutes  B) 30 minutes  C) 40 minutes  D) 50 minutes  E) 60 minutes
Total work done by both machines in a minute = 15 + 10= 
<gadget id="calculator">15 + 10</gadget>
<output>25</output>
25 copies   Total number of copies required= 1000   Time = 1000/25= 
<gadget id="calculator">1000/25</gadget>
<output>40</output>
40 mins   Answer 40 minutes
<result>C</result>
One copy machine can make 15 copies a minute, and a second copy machine makes 10 copies a minute. If the two copiers work together, how long would it take them to make 1,000 copies?