A pack of motorcyclists just whizzed down my street, mostly on two-wheeled Harleys but a few on Slingshots (three-wheeled). I counted 8 cyclists. My friend counted 19 wheels (the cycles were spread out enough so your friend could make this count). How many of the cycles were Harleys and how many were Slingshots?
Solution
With 8 cyclists there are at least 16 wheels, but there are 19 wheels. The extra 3 mean there are 3 Slingshots and 5 Harleys. Question: why did your friend decide to count wheels?