12 speed bike has 12 speeds?

[Clint]

A twelve speed bike implies that it has 12 different speeds.
Explain how this can occur. (diagrams would be useful)

 

[Scamp]

12 speed bike simple means there is up to 12 different gear combination's you can use.

Generally you have 2 different size sprockets that you pedal and 6 different size sprockets on the wheel. Depending on how you shift the chain up and down on the pedals and wheel, you have 12 different combination's ranging from easy pedaling=slow speed=more torque to hard pedaling=faster speed=less torque.