Question P6 An average is a total
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Tammy has 3 boxes of apples. Box A is 550 g heavier than Box B and 770 g heavier than Box C. The average mass of the 3 boxes is 2150 g. What is the average mass of Box B and Box C?
Answer
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Turn the average back into a total before doing anything with it.
In this one. An average is a disguised total — 3 × 2150 = 6450 g — and once every box is written against the smallest one, the three bars level to a common length and the two given extras (220 g and 770 g) can be cut off that total.
The word 'average' appears alongside a group being split into two parts, or two separate journeys or trips being combined into one overall figure.
Children average two averages directly, such as averaging two speeds or two group averages, without weighting by how many, or how long, each part actually covers.
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