Find avrg speed if a man travels at speed of 15km/hr up and 28km/hr dawn at an altitude of 230m. Select the correct option:
A) 25.8  B) 19.5  C) 18.0  D) 12.2  E) 29.8
avg speed=2*x*y/(x+y)   =2*15*28/(15+28)=19.5   ANSWER:19.5
<result>B</result>
Find avrg speed if a man travels at speed of 15km/hr up and 28km/hr dawn at an altitude of 230m.