Question P6 An average is a total
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The mean age of four cousins is 12 years. Three of the cousins are 9, 13, and 15 years old. Find the age of the fourth cousin.
Answer
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Turn the average back into a total before doing anything with it.
In this one. An average is the total shared equally, so multiply the mean by the number of cousins to recover the total, then subtract the known ages.
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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