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A car travels for 18 minutes at an average speed of 72 km/h - Edexcel - GCSE Maths - Question 10 - 2019 - Paper 1
Question 10
A car travels for 18 minutes at an average speed of 72 km/h. (a) How far will the car travel in these 18 minutes? David says. "72 kilometres per hour is faster th... show full transcript
Worked Solution & Example Answer:A car travels for 18 minutes at an average speed of 72 km/h - Edexcel - GCSE Maths - Question 10 - 2019 - Paper 1
Step 1
How far will the car travel in these 18 minutes?
Answer
To calculate the distance travelled by the car, we can use the formula:
Given that the speed is 72 km/h, we first need to convert the time from minutes to hours. Since there are 60 minutes in an hour, we convert 18 minutes as follows:
ext{Time in hours} = rac{18}{60} = 0.3 ext{ hours}Now, substituting in the values:
Thus, the car will travel 21.6 km in 18 minutes.
Step 2
Is David correct?
Answer
To determine if David is correct, we need to compare 72 km/h with 20 m/s.
First, convert 72 km/h to meters per second: 1 km = 1000 meters and 1 hour = 3600 seconds. Thus,
72 ext{ km/h} = 72 imes rac{1000}{3600} ext{ m/s} = 20 ext{ m/s}Since 72 km/h equals 20 m/s, David's statement "72 kilometres per hour is faster than 20 metres per second" is incorrect. Therefore, David is not correct.