The boat moves downside 50km and upside 10km in 2 hours each. Then find the boat speed in still water?  Choose the correct option
A) 10km/hr	B) 15km/hr	C) 20km/hr	D) 25km/hr	E) 30km/hr
Down stream = 50/2= 
<gadget id="calculator">50/2</gadget>
<output>25</output>
25km/hr   Up stream= 10/2= 
<gadget id="calculator">10/2</gadget>
<output>5</output>
5km/hr   speed of boat in still water= 30/2= 
<gadget id="calculator">30/2</gadget>
<output>15</output>
15km/hr   Answer is 15km/hr
<result>B</result>
The boat moves downside 50km and upside 10km in 2 hours each. Then find the boat speed in still water?