On a trip covering 350 km, a bicyclist travels the first 200 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?
Choose the correct choice from the following.
A) 15.5 B) 16.0 C) 17.5 D) 19.0 E) 18.5
time 1 = 200 / 20= 
<gadget id="calculator">200 / 20</gadget>
<output>10</output>
10 hours   time 2= 150 / 15= 
<gadget id="calculator">150 / 15</gadget>
<output>10</output>
10 hours   total time= 20 hours   average speed = 350 / 20= 
<gadget id="calculator">350 / 20</gadget>
<output>35/2 = around 17.5</output>
17.5 km/hr   The answer is 17.5.
<result>C</result>
On a trip covering 350 km, a bicyclist travels the first 200 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?