A survey of 1108 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 both a bus and a train and 321 employees take only a train. To the nearest percent find the probability that a randomly chosen employee takes a bus or a train to work.
445 employees take a train to work and 321 take only a triain
445 - 321 = 124 take both a bus and train to work
So.....621 - 124 = 497 take only a bus
So the probability that an employee takes a bus or train (but not both) =
[ 321 + 497 ] / 1108 =
818 / 1108 ≈ .738 = 73.8%