A boat moves upstream at the rate of 1 km in 20 minutes and down stream 1 km in 12 minutes. Then the speed of the current is :	Choose one:	A) 1 kmph	B) 2 kmph	C) 3 kmph	D) 2.5 kmph	E) 3.5 kmph
Rate upstream = (1/20 *60)= 
<gadget id="calculator">(1/20 *60)</gadget>
<output>3</output>
3 kmph   Rate dowm stream= 1/12 * 60= 
<gadget id="calculator">1/12 * 60</gadget>
<output>5</output>
5 kmph   Rate of the current= ½ (5-3) = 1 kmph   1 kmphNSWER:1 kmph
<result>A</result>
A boat moves upstream at the rate of 1 km in 20 minutes and down stream 1 km in 12 minutes. Then the speed of the current is :