Running at the same constant rate, 6 identical machines can produce a total of 270 pens per minute. At this rate, how many pens could 10 such machines produce in 4 minutes?
Choices
A) 1500  B) 1545.6  C) 1640.33  D) 1800  E) None of these
Explanation :   Let the required number of bottles be x.   More machines, More bottles (1800irect Proportion)   More minutes, More bottles (1800irect Proportion)   machines 6:10|   |::270:x   time 1:4 |   =&gt; 6 * 1 * x = 10 * 4 * 270   =&gt; x = (10 * 4 *270)/6   =&gt; x = 1800   Answer : 1800
<result>D</result>
Running at the same constant rate, 6 identical machines can produce a total of 270 pens per minute. At this rate, how many pens could 10 such machines produce in 4 minutes?