Running at the same constant rate,6 identical machines can produce a total of 270 bottles per minute.At this rate,how many bottles could 20 such machines produce in 4 minutes ?	Choose the correct choice from the following choices:
A) 648
B) 1800
C) 2700
D) 10800
E) 3600
Solution   Let the required number of bottles be x.   More machines,More bottles (Direct Proportion)   More minutes,More bottles (Direct Proportion)   âˆ´ 6 Ã— 1 Ã— x = 20 Ã— 4 Ã— 270 â‡” x = 20x4x270/6= 3600 . Answer 3600
<result>E</result>
Running at the same constant rate,6 identical machines can produce a total of 270 bottles per minute.At this rate,how many bottles could 20 such machines produce in 4 minutes ?