Question 45:
A tourist bus covers a distance of 500 kilometers. It travels the first 40% of the distance at a speed of 80 km/hr and the rest of the distance at 75 km/hr. If it takes a 30-minute stop for lunch during the journey, what is the average speed for the entire trip? (Rounded off to two decimal places.)
Options :
- a) 71.43 km/hr
- b) 76.92 km/hr
- c) 75 km/hr
- d) 72.54 km/hr
correct answer : a)
Explanation :
First distance = 40% of 500 = 200 km at 80 km/h ⇒ Time t1 = 200/80 = 2.5 hrs.
Remaining distance = 300 km at 75 km/h ⇒ Time t2 = 300/75 = 4 hrs.
Lunch break = 30 min = 0.5 hr.
Total elapsed time = 2.5 + 4 + 0.5 = 7 hrs.
Average Speed = Total Distance / Total Time = 500 / 7 = 71.43 km/hr.