Circular gears \(P\) and \(Q\) start rotating at the same time at constant speeds. Gear \(P\) makes \(10\) revolutions per minute and Gear \(Q\) makes \(40\) revolutions per minute. How many seconds after the gears start rotating will gear \(Q\) have made exactly \(6\) more revolutions than gear \(P?\)

A. 6
B. 8
C. 10
D. 12
E. 15

Answer: D

Source: GMAT Prep