Question

Tim goes on a car journey.

For the first 15 minutes his
average speed is 40 mph.
He then stops for
25 minutes.
He then completes the
journey at an average
speed of 45 mph.
The total journey time
is 1 hour.
a) Draw a distance-time
graph for his journey.
b) What is the average
speed for the whole
journey?
mph

Answer 1

2. 25 mph

Explanation:

1. Tim travels first 15 minutes hour at average speed of 40 mph and passed

2. Time stops for 25 minutes (distance traveled = 0 miles).

3. He then completes the journey at an average speed of 45 mph. The total journey time is 1 hour, then he was travelling at 45 mph for

and covered

The distance-time graph for his journey is attached.

Find the average speed for the whole journey:

Answer:

1. Attached

2. 25 mph

Explanation:

1. Tim travels first 15 minutes hour at average speed of 40 mph and passed

2. Time stops for 25 minutes (distance traveled = 0 miles).

3. He then completes the journey at an average speed of 45 mph. The total journey time is 1 hour, then he was travelling at 45 mph for

and covered

The distance-time graph for his journey is attached.

Find the average speed for the whole journey:

Answer 2

1. Attached

2. 25 mph

Explanation:

1. Tim travels first 15 minutes
`=(1)/(4)` hour at average speed of 40 mph and passed

`40* (1)/(4)=10\ miles`

2. Time stops for 25 minutes (distance traveled = 0 miles).

3. He then completes the journey at an average speed of 45 mph. The total journey time is 1 hour, then he was travelling at 45 mph for

`60-15-25=20\ minutes=(1)/(3)\ hour`

and covered

`45* (1)/(3)=15\ miles.`

The distance-time graph for his journey is attached.

Find the average speed for the whole journey:

`\text{Average speed}=\frac{\text{Total distance}}{\text{Total time}}=(10+15)/(1)=25\ mph`