median
don steward
mathematics teaching 10 ~ 16

Wednesday, 22 December 2010

Christmas cards

a person is talking to three maths teachers about how many cards they were each given by their students




they don't answer straight away but make it into a problem instead
"the product of our numbers of cards is 36"
"OK but
you'll need to tell me more"

"well the sum of our number of cards is the number of cards that Anna (an English teacher) got"

the person goes to see Anna and finds out how many cards she got and returns,
"but I still need a further clue"

"well, the one of us who got the most cards is female"

the person then knows how many cards they each got

how?

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