The diagram is the distance time graph of a vehicle. Find its average speed in kilometers per hour during the journey

A.
155km/hr 
B.
50km/hr 
C.
40km/hr 
D.
124km/hr 
E.
84km/hr
Correct Answer: Option E
Explanation
Distance = 155 – 50 = 105km
Time = 75mins
= (frac{75}{60})hr = (frac{5}{4})hr
Average speed = (frac{Distance}{time}) = (frac{105}{frac{5}{4}})
= (frac{105 times 4}{5})
= 84kmh