Question

A bus driver takes a total of three hours to make a journey of 120 km. During the journey, he takes

a break of 10 minutes at a cafe and spend 30 minutes taking a nap in the bus.
At what average speed must he travel during the rest of the time to complete the journey in three
hours?

Answer 1

Answer: He must travel approximately 51.5 km per hour.

Explanation:

So first, let's turn our hours into minutes;

3 hours = 180 minutes.

Now let's add up the time that the bus driver is not driving;

10 minutes + 30 minutes = 40 minutes not traveled.

Let's subtract the time he doesn't travel from the total number of minutes;

180 - 40 = 140 minutes.

So now we know that it takes him 140 minutes to travel 120 km.

Now let's figure out how many hours is equal to 140 minutes. We'll do that by dividing 140 by 60;

140/60 = approximately 2.33 hours.

In order to find out the speed, we must divide the distance (120 km) by the time (2.33 hours);

120km/2.33 hours = approximately 51.5 km per hour.

He does not travel a full three hours, only around 2.33 hours. So therefore, he must travel at approximately 51.5 km per hour.

Answer 2

14.3 m/s

Explanation:

speed = distance/time

time = 3 hours = 180 minutes

180 - 40 = 140

140 minutes = 8400 seconds

distance = 120 km = 120000 m

speed = 120000/8400

= 14.2857