A person covers a distance in 6 minutes. If runs at a speed of 12 km per hour on an average. Find the speed at which he must run to reduce the time of journey to 5 minutes.
Choose the correct choice from the following:
A) 18 m/s B) 4 m/s C) 15 m/s D) 10 m/s E) 5 m/s
Explanation:   T = 6 m   Spees = 12 kmph   = 12 x 5/18 = 10/3 m/s   Let new speed be "x"   6 x (10/3) = 5x   x = 4 m/s   Answer: Option 4 m/s
<result>B</result>
A person covers a distance in 6 minutes. If runs at a speed of 12 km per hour on an average. Find the speed at which he must run to reduce the time of journey to 5 minutes.