Preeti covers a distance in 40 min , if she drives at a speed of 60 km/h on an average. Find the speed at which she must drive at to reduce the time of the journey by 50%.  Answers:
A) 60 km/h	B) 70 km/h	C) 117.64 km/h	D) 100 km/h	E) 125.25 km/h
Given Speed = 60 Kmph.   It means Preeti covered 60 km in 60 min (1 hour). So, in 40 min he will cover 40 km.   50% time reduced = 40 - 50% of 40 = 20 min.   Thus, Preeti needs to cover 40 km in 20 min (0.34 hour).   Speed * Time = Distance.   Speed * 0.34 = 40   Speed = 117.64 kmph.   ANSWER : OPTION 117.64 km/h
<result>C</result>
Preeti covers a distance in 40 min , if she drives at a speed of 60 km/h on an average. Find the speed at which she must drive at to reduce the time of the journey by 50%.