A boat moves upstream at the rate of 1 km in 20 minutes and down stream 1 km in 9 minutes. Then the speed of the current is :  Choose the correct choice from the following: A) 1 kmph B) 2 kmph C) 3 kmph D) 2.5 kmph E) 1.85 kmph
Rate upstream = (1/20 *60)= 
<gadget id="calculator">(1/20 *60)</gadget>
<output>3</output>
3 kmph   Rate dowm stream= 1/9 * 60 = 6.7 kmph   Rate of the current = ½ (6.7-3) = 1.85 kmph   ANSW1.85 kmphR:1.85 kmph
<result>E</result>
A boat moves upstream at the rate of 1 km in 20 minutes and down stream 1 km in 9 minutes. Then the speed of the current is :