Running at the same constant rate, 6 identical machines can produce a total of 420 bottles per minute. At this rate, how many bottles could 10 such machines produce in 4 minutes?	Answers.
A) 648	B) 1800	C) 2800	D) 10800	E) 10900
Let the required number of bottles be x.   More machines, More bottles (Direct Proportion)   More minutes, More bottles (Direct Proportion)   Machines	6	:	10	:: 420 : x   Time (in minutes)	1	:	4   6 x 1 x x = 10 x 4 x 420   x =	(10 x 4 x 420)/(6)   x = 2800.   ANSWER:2800
<result>C</result>
Running at the same constant rate, 6 identical machines can produce a total of 420 bottles per minute. At this rate, how many bottles could 10 such machines produce in 4 minutes?