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Snow White wanted to know the mean height of the Seven Dwarfs. So one day she measured them all as they left for work and calculated their mean height as 112.3 cm. Doc complained that she had left him out and measured Dopey twice without him noticing. If Doc is 3 cm taller than Dopey, what is the mean height of the Seven Dwarfs (correct to one decimal place)?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.