DistanceandTime
Question 1 
In a 100 meters race, A beat B by 10 meter or 2 second. What is the speed of A?
5 Km/h  
10 Km/h  
15 Km/h
 
20 Km/h

Question 1 Explanation:
When A completes 100m, B is at 90m which is 10m behind.Now A beats B by 2 secs.
This means B takes 2 more seconds to complete the race
As B is 10m behind when A completes the race, so B takes 2 secs to complete 10m
Speed of B = 5m/s
Total time of B = 100/5 = 20 secs
Time of A = 20  2 = 18 seconds
Speed of A = 100/18 = 5.555
This means B takes 2 more seconds to complete the race
As B is 10m behind when A completes the race, so B takes 2 secs to complete 10m
Speed of B = 5m/s
Total time of B = 100/5 = 20 secs
Time of A = 20  2 = 18 seconds
Speed of A = 100/18 = 5.555