Time And Distance

Time And Distance
1.   A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour?
A.  3.6  B.  7.2
C.  8.4  D.  10
Answer: Option B
Explanation:

Speed =600/(5*60)m/sec.

        = 2 m/sec.
Converting m/sec to km/hr = 2x(18/5) km/hr

=7.2km/hr

2.   An aeroplane covers a certain distance at a speed of 240 kmph in 5 hours. To cover the same 
distance in 1  hours, it must travel at a speed of:

A.  300 kmph  B.  360 kmph
C.  600 kmph  D.  720 kmph

Answer: Option D

Explanation:
Distance = (240 x 5) = 1200 km.
Speed = Distance/Time 
Speed = 1200/(5/3) km/hr.     [We can write 1  hours as 5/3 hours]
Required speed = 1200x(3/5)km/hr

= 720 km/hr.

3.   If a person walks at 14 km/hr instead of 10 km/hr, he would have walked 20 km more. The actual 
distance travelled by him is:
A.  50 km  B.  56 km
C.  70 km  D.  80 km
Answer: Option A
Explanation:
Let the actual distance travelled be x km.
Then,
x/10=(x + 20)/14
=) 14x = 10x + 200
=) 4x = 200
=)x = 50 km.