In a parking lot, there are cars and motorcycles. Each car has 5 wheels (including one spare) and each motorcycle has 2 wheels. There are 19 cars in the parking lot. Altogether all vehicles have 117 wheels. How many motorcycles are at the parking lot? Let's think first. Chain of thought:
There are 19 cars at the lot, so there are 5 * 19 = 95 wheels of cars. So there are 117 - 95 = 22 wheels of motorcycles in the parking lot. Each motorcycle has 2 wheels, so that leaves us with 22 / 2 = 11 motorcycles in the parking lot.
Therefore, the answer is 11.