On a trip covering 400 km, a bicyclist travels the first 100 km at 20 km per hour and the remainder of the distance at 15 km per hour. What is the average speed, in km per hour, for the entire trip?	Answers.
A) 15.5 B) 16.0 C) 16.5 D) 17.0 E) 17.5
time 1 = 100 / 20= 
<gadget id="calculator">100 / 20</gadget>
<output>5</output>
5 hours   time 2= 300 / 15= 
<gadget id="calculator">300 / 15</gadget>
<output>20</output>
20 hours   total time= 25 hours   average speed = 400 / 25= 
<gadget id="calculator">400 / 25</gadget>
<output>16</output>
16 km/hr   The answer is 16.0.
<result>B</result>
On a trip covering 400 km, a bicyclist travels the first 100 km at 20 km per hour and the remainder of the distance at 15 km per hour. What is the average speed, in km per hour, for the entire trip?