Truck P and Truck Q drive on the highway in the same direction at respective rates of 70 kph and 77 kph. If Truck Q is 4 km behind Truck P, by how much does Truck P need to increase the speed to catch up with Truck P in 15 minutes?	Choose the correct choice from the following:
A) 1 kph	B) 3 kph	C) 5 kph	D) 7 kph	E) 9 kph
Truck Q needs to gain 4 km in 15 minutes.   The relative speed difference needs to be 4 km / 15 minutes = 16 km/hour   Truck Q needs to increase up to 86 kph, thus an increase in 9 kph.   The answer is 9 kph.
<result>E</result>
Truck P and Truck Q drive on the highway in the same direction at respective rates of 70 kph and 77 kph. If Truck Q is 4 km behind Truck P, by how much does Truck P need to increase the speed to catch up with Truck P in 15 minutes?