Question P6 An average is a total
Today’s problem — free all day, every step. Every day has one.
The mean amount of money saved by four pupils in a week is $18.50. Three of them saved $15, $20.50, and $22.50. How much did the fourth pupil save?
Answer
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Turn the average back into a total before doing anything with it.
In this one. An average is a total shared out equally: multiply the mean by the number of pupils to recover the total, then subtract the parts already known.
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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