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A grain of salt weighs 6.48 x 10^-5 kg on average - OCR - GCSE Maths - Question 17 - 2019 - Paper 1
Question 17
A grain of salt weighs 6.48 x 10^-5 kg on average. A packet contains 0.35 kg of salt. (a) Use this information to calculate the number of grains of salt in the pa... show full transcript
Worked Solution & Example Answer:A grain of salt weighs 6.48 x 10^-5 kg on average - OCR - GCSE Maths - Question 17 - 2019 - Paper 1
Step 1
Use this information to calculate the number of grains of salt in the packet.
Answer
To calculate the number of grains of salt in the packet, we can use the formula:
ext{Number of grains} = rac{ ext{Total weight of salt}}{ ext{Weight of one grain of salt}}Substituting the values:
ext{Number of grains} = rac{0.35 ext{ kg}}{6.48 imes 10^{-5} ext{ kg}}Calculating this gives:
Rounding to the appropriate significant figures, the final answer is 5400.
Step 2
Explain why your answer to part (a) is unlikely to be the actual number of grains of salt in the packet.
Answer
The calculated number of grains of salt is an average based on the weight of a single grain. In reality, the weight of individual grains can vary due to factors such as:
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Variation in Size: Grains of salt can differ in size, leading to variations in weight. Therefore, while the average is useful for estimation, some grains may weigh less and some may weigh more.
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Environmental Factors: Humidity and the method of harvesting or production can lead to differences in grain weight.
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Integer Requirement: The actual number of grains must be an integer. As the result is approximately 5400.123, it indicates that the actual count could not be exactly this number, suggesting discrepancies in the total weight or the average weight used for calculations.