Q16. 
Rajesh walks to and fro to a shopping mall. He spends 30 minutes shopping. If he walks at speed of 10 km an hour, he returns to home at 19.00 hours. If he walks at 15 km an hour, he returns to home at 18.30 hours. How fast must he walk in order to return at 18.15 hours? 
A.  17 km/hr 

B.  18 km/hr 

C.  19 km/hr 

D.  20 km/hr 
Q18. 
A bus without stopping travels at an average speed of 60 km/hr and with stoppages at an average speed of 40 km/hr. What is the total time taken by the bus for stoppages on a route of length 300km? 
A.  4 hr 

B.  3 hr 

C.  2.5 hr 

D.  3.5 hr 
Q19. 
Distance between the points is $P$. $A$ man with the speed of $s$ and reaches the other point late by 2 hours. Calculated the speed with which the man has to travel to reach in time, where t is the actual time. 
A.  \(\dfrac{S\times (t+1)}{(t+2)}\) 

B.  \(\dfrac{s\times t}{(t+2)}\) 

C.  \(\dfrac{s\times (t+2)}{t}\) 

D.  \(\dfrac{s\times t}{(t+1)}\) 
Q20. 
The speed of a bus during the second hour of its journey is twice that in the first hour. Also, its speed during the third hour is twothird the sum of its speeds in the first two hours. Had the bus travelled for three hours at the speed of the first hour, it would have travelled 120 km less. Find the average speed of the bus for the first three hours. 
A.  60 kmph 

B.  70 kmph 

C.  80 kmph 

D.  100 kmph 