Directions : The following questions are based on the table given below which represents the distance (in km) travelled by two persons A and B in the same direction.
Hour 
Distance Travelled (in Km) 

A  B  
1st  10  20 
2nd  20  25 
3rd  30  30 
4th  40  50 
What is the average speed of B during the first three hours?
The average speed of B during the first three hours
\[=\frac{20+25+30}{3}\]
\[=25\] km/h