Asurvey of 1,108 employees at a software company finds that 621 employees take a bus to work and 445 employees take a train to work. some employees take a bus and a train, and 321 employees only take a train. to the nearest percent, find the probability that a randomly chosen employee takes a bus or a train to work. explain.

We know 445 employees take the train, and that 321 of these exclusively take the train. So 445 - 321 = 124 take both the train and bus.

Now, if is the set of employees that take the bus and the set of employees that take the train, then



where is the number of employees belonging to a general set .

So the probability that an employee takes either the bus or train is