Answer: his speed would be 40 km/h.
Step-by-step explanation: To solve this problem, let's consider a few basic concepts from physics, specifically those involving speed, distance, and time.
Part (a): Finding the time to cover the same distance at a different speed.
Given:
Speed = 60 km/h
Time = 40 minutes (which is
40
60
=
2
3
60
40
=
3
2
hours)
Step 1: Calculate the Distance.
Since speed equals distance divided by time, you can rearrange this to find distance:
Distance
=
Speed
×
Time
Distance=Speed×Time
So, the distance covered at 60 km/h for 40 minutes (or
2
3
3
2
hours) is:
Distance
=
60
×
2
3
=
40
km
Distance=60×
3
2
=40 km
Step 2: Determine Time to Cover the Same Distance at 50 km/h.
Now that you know the distance (40 km), find the time taken to cover it at 50 km/h:
Time
=
Distance
Speed
Time=
Speed
Distance
Time
=
40
50
=
4
5
hours
Time=
50
40
=
5
4
hours
To convert
4
5
5
4
hours to minutes, multiply by 60:
4
5
×
60
=
48
minutes
5
4
×60=48 minutes
Thus, he will take 48 minutes to cover the same distance at a speed of 50 km/h.
Part (b): Finding the speed when covering the same distance in a different time.
Given the same distance (40 km), let's find the speed if it's covered in 60 minutes (or 1 hour):
Speed
=
Distance
Time
Speed=
Time
Distance
Speed
=
40
1
=
40
km/h
Speed=
1
40
=40 km/h
Therefore, if he covers the same distance in 60 minutes, his speed would be 40 km/h.