Question
The pyramid P is formed from two parts made of different materials. The top part of P has a mass of 92.8 g and is made from material with a density of 2.9 g/cm³. The bottom part of P has a mass of 972.8 g. The average density of P is 4.7 g/cm³. Calculate the volume of the top part of P as a percentage of the total volume of P. Give your answer correct to 1 decimal place. You must show all your working.
Worked Solution
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Find the volume of the top part: volume = mass ÷ density = 92.8 ÷ 2.9 = 32 cm³.
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Find the total mass of pyramid P: 92.8 + 972.8 = 1065.6 g.
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Find the total volume of pyramid P using the average density: total volume = total mass ÷ average density = 1065.6 ÷ 4.7 ≈ 226.72 cm³.
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Express the volume of the top part as a percentage: (32 ÷ 226.72) × 100 ≈ 14.1%.
14.1
Using the wrong density for the total volume calculation — the average density 4.7 g/cm³ applies to the whole pyramid, not just one part. Make sure to use total mass and average density together.
Assessment Objectives (question level, Edexcel 1MA1 spec — not per step)