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 10 more revolutions than gear P?
Pick
A) 10	B) 12	C) 15	D) 20	E) 25
Gear Q makes 30 more revolutions each 60 seconds.   The time to make 10 = 30/3 more revolutions is 60/3= 
<gadget id="calculator">60/3</gadget>
<output>20</output>
20 seconds.   The answer is 20.
<result>D</result>
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 10 more revolutions than gear P?