There are two soda machines at a school. A can soda costs $.75 from Machine A and works 100% of the time. A can of soda from Machine B costs $.50 and this machine works 60% of the time. When B doesn't work, it eats your money. You determine the following strategy: Try Machine B. If it does not work, go to Machine A and purchase our soda from it.
Evaluate this strategy in the long run.