A wheel that has 6 cogs is meshed with a larger wheel of 21 cogs. When the smaller wheel has made 21 revolutions, then the number of revolutions mad by the larger wheel is:	Pick one.
A) 49  B) 4  C) 12  D) 6  E) 27
Let the required number of revolutions made by larger wheel be x.   Then, More cogs, Less revolutions (Indirect Proportion)   21 : 6 :: 21 : x 21 * x = 6 x 21   x =	(6 x 21)/21   x = 6   Answer is 6.
<result>D</result>
A wheel that has 6 cogs is meshed with a larger wheel of 21 cogs. When the smaller wheel has made 21 revolutions, then the number of revolutions mad by the larger wheel is: