A river boat leaves Silver Town and travels upstream to Gold Town at an average speed of 6 kilometers per hour. It returns by the same route at an average speed of 8 kilometers per hour. What is the average speed for the round-trip in kilometers per hour? Select
A) 6.8	B) 7.1	C) 7.2	D) 7.5	E) 8.0
Pick a number which is LCM of 8 and 6 = 24.   Upstream time = 24/6= 
<gadget id="calculator">24/6</gadget>
<output>4</output>
4 hrs   Downstream time= 24/8= 
<gadget id="calculator">24/8</gadget>
<output>3</output>
3 hrs   Total time= 7 hrs   Total distance = 48   6.8verage Speed = 48/7 =6.8km/hr
<result>A</result>
A river boat leaves Silver Town and travels upstream to Gold Town at an average speed of 6 kilometers per hour. It returns by the same route at an average speed of 8 kilometers per hour. What is the average speed for the round-trip in kilometers per hour?