one prototyping machine can make 10 copies every 4 seconds. At this rate, How many copies
can the machine make in 6 min.?  Select the correct option: A) 900 B) 600 C) 360 D) 240 E) 150
10 copies--4 sec   10/4 copies--1 sec   (10/4)*6*60---1*6*60 sec   900 copies--6 min   900NSWER:900
<result>A</result>
one prototyping machine can make 10 copies every 4 seconds. At this rate, How many copies
can the machine make in 6 min.?