Sujal 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 25%.
Choose the most appropriate option.
A) 60 km/h  B) 70 km/h  C) 75 km/h  D) 80 km/h  E) 85 km/h
Given Speed = 60 Kmph.   It means Sujal covered 60 km in 60 min (1 hour). So, in 40 min he will cover 40 km.   25% time reduced = 40 - 25% of 40 = 30 min.   Thus, Sujal needs to cover 40 km in 30 min (0.5 hour).   Speed * Time = Distance.   Speed * 0.5 = 40   Speed = 80 kmph.   ANSWER : OPTION 80 km/h
<result>D</result>
Sujal 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 25%.