Enigma 1611: Three sisters
30 December 2011
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From New Scientist #2776, 4th September 2010 [link]
I have three aunts whose ages on their birthdays this year will each be a different prime. I would not dare to call them elderly, but at least one of them will be in her fifties. They were reminiscing that the last time their ages on their birthdays had all been prime in one year was 30 years ago, and on the occasion before that two of them had been in their teens.
“I wonder,” one of them said, “if we will be alive when it happens again?”
“I don’t see why not,” another replied, “for it will happen before any of us reaches 80.”
What will their ages be on their birthdays this year?