A boat goes 100 km downstream in 10 hours, and 90 km upstream in 15 hours. The speed of the stream is? Choose the correct choice from the following answers
A) 5km/h	B) 4km/h	C) 2km/h	D) (1/2) km/h	E) E)None
100 --- 10 DS = 10   ? ---- 1   90 ---- 15 US = 6   ? ----- 1 S = (10 - 6)/2= 
<gadget id="calculator">(10 - 6)/2</gadget>
<output>2</output>
2 kmph   ANSWER:2km/h
<result>C</result>
A boat goes 100 km downstream in 10 hours, and 90 km upstream in 15 hours. The speed of the stream is?