The train travels at an average speed of 16km/h, to the top of the hill where the midpoint of the trip is. Going down hill, train travels at an average speed of 8km/h. Which of the following is the closest approximation of train's average speed, in kilometers per hour, for the round trip?	Options:
A) 9.6
B) 10.6
C) 4.3
D) 2.5
E) 5.3
Since we're not given a distance to work with, we can TEST any distance that we like. Here, since the speeds are 16km/hour and 8 km/hour, using a multiple of both 16 and 8 would make the math easiest.   Let's set the Distance up the hill at 64 km.   So, going uphill, we have....   D = (R)(T)   64 = (16)(T)   64/16= 
<gadget id="calculator">64/16</gadget>
<output>4</output>
4= T   4 hours to go uphill   Going downhill, we have....   D = (R)(T)   60 = (20)(T)   64/8= 
<gadget id="calculator">64/8</gadget>
<output>8</output>
8= T   8 hours to go downhill   Total Distance = 120 km   Total Time = 4+8= 
<gadget id="calculator">4+8</gadget>
<output>12</output>
12 hours   Average Speed= 128/12 = 10.6 km/hour   10.6
<result>B</result>
The train travels at an average speed of 16km/h, to the top of the hill where the midpoint of the trip is. Going down hill, train travels at an average speed of 8km/h. Which of the following is the closest approximation of train's average speed, in kilometers per hour, for the round trip?