A person has to cover a distance of 6 km in 45 minutes. If he covers one-half of the distance in two-thirds of the total time; to cover the remaining distance in the remaining time, his speed (in km/hr) must be :
Select:
A) 7 km/hr
B) 8 km/hr
C) 11 km/hr
D) 12 km/hr
E) None of these
Sol.   Remaing distance = 3 km and   Remaining time = [1/3 * 45= 
<gadget id="calculator">1/3 * 45</gadget>
<output>15</output>
15 min= 1/4 hour.   ∴ Required speed = (3*4) km/hr = 12 km/hr.   Answer 12 km/hr
<result>D</result>
A person has to cover a distance of 6 km in 45 minutes. If he covers one-half of the distance in two-thirds of the total time; to cover the remaining distance in the remaining time, his speed (in km/hr) must be :