Mathew usually makes the 100 km journey to visit his family. The trip involves three separate stages:
a) A stage of 20 km that is travelled on small roads at a constant speed of 30 km/h.
b) A stage of 50 km that is travelled on the highway at a constant speed of 100 km/h.
c) A stage of 30 km that is travelled on standard roads at a constant speed of 40 km/h.
1- How long does it normally take Paul to make this journey? Last week there were roadworks on a section of the highway, and Paul was only able to travel at 60 km/h for the length of the roadworks. Paul’s journey last week took 6 minutes longer than usual.
2- What was the length of the section of roadworks?

In this exercise we have to use the knowledge of time and distance, so we have to:  

1) Total time = 1 hr 55 minutes

2) Distance = 121 km

To calculate Matthew's journey we have to use the formula of :

Are doing the calculations for each Stage, like this:

Stage A, we know that:

Stage B, we know that:  

Stage C, we know that:  

1) So using all the values calculated above, let's calculate the total value of the trip that will take place by:

2) For the second part of this question we want to calculate the total distance of travel hours so:  

See more about time and disatnce at link

1 . Total time = 1 hr 55 minutes

2 Distance = 121 km

Step-by-step explanation:

Mattew journey

stage a

Distance = 20km

Speed = 30km/h

Time = distance/speed

Time = 20/30

Time = 2/3 h

Time = 40 minutes

Stage b

Distance = 50 I'm

Speed = 100 km/h

Time = distance/speed

Time = 50/100

Time = 0.5 h

Time = 30 minutes

Stage c

Distance = 30 km

Speed = 40 km/h

Time = distance/speed

Time = 30/40

Time = 3/4 h

Time = 45 minutes.

Total time taken =( 40 + 30 + 45 ) minutes

Total time = 115 minutes

Total time = 1 hr 55 minutes

2.

Speed =60 km/h

Time= 6 minutes + x

And x = 1 hr 55 minutes

Time = 1 hr 55 minutes + 6 minutes

Time = 2 hr 1 minute

Time = 2.01666667 hr

Distance covered = speed * time

Distance = 60*2.016667

Distance = 121 km