Identical bikes and a total spoke count
Question
A shop has at least bikes, all identical; each wheel has at least one spoke, but a bike's front and rear wheels may differ. The shop's total spoke count is between and . You are told that, if you learned that total, you could deduce the number of bikes for certain. That fact alone lets you work out how many bikes there are. How many?
Short answer
. The total is with bikes and spokes per bike. The bike count is determined only if has exactly one such factorisation, which happens only when for a prime . The only one in is , so there are bikes.
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