Arron ran a distance of 5km at an average speed of 2.2m/s - OCR - GCSE Maths - Question 15 - 2019 - Paper 1
Question 15
Arron ran a distance of 5km at an average speed of 2.2m/s.
How long did Arron run for?
Give your answer in minutes and seconds, to the nearest second.
(b) Claudine... show full transcript
Worked Solution & Example Answer:Arron ran a distance of 5km at an average speed of 2.2m/s - OCR - GCSE Maths - Question 15 - 2019 - Paper 1
Step 1
How long did Arron run for?
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Answer
To determine how long Arron ran, we start with the formula for time:
t=sd
In this case, the distance (
d
) is 5 km and the speed (
s
) is 2.2 m/s. First, we need to convert the distance into meters:
5extkm=5000extm
Now, substituting the values into the time formula:
t=2.2extm/s5000extm≈2272.73extseconds
Next, we convert seconds into minutes:
2272.73extseconds≈37extminutes and 52.73extseconds.
Rounding to the nearest second, Arron ran for approximately 37 minutes and 53 seconds.
Step 2
Calculate the lower and upper bounds of her average speed.
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Answer
The distance Claudine cycled is 53 km, with a measurement correct to the nearest kilometer. This implies:
Lower bound for distance = 52.5 km
Upper bound for distance = 53.5 km
The time taken is 2.7 hours, measured to 1 decimal place:
Lower bound for time = 2.65 hours
Upper bound for time = 2.75 hours
To find the average speed bounds, we apply the formula for average speed: