A Fisher man can row 4 km against the stream in 30 minutes and returns in 20 minutes. What is the speed of the current?	Choose the correct option.
A) 1 km/hr  B) 2 km/hr  C) 3 km/hr  D) 4 km/hr  E) 5 km/hr
Explanation:   Speed up stream = (4/30) × 60 = 8 km/hr   Speed down stream = (4/20) × 60 = 12 km/hr   Speed of current = 1/2 (12 - 8) = 4/2= 
<gadget id="calculator">4/2</gadget>
<output>2</output>
2 km/hr   Answer: Option 2 km/hr
<result>B</result>
A Fisher man can row 4 km against the stream in 30 minutes and returns in 20 minutes. What is the speed of the current?