Find the probability

Question

Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 78 people in the 18-21 age bracket and finds that 66 of them respond and 12 refuse to respond. When 278 people in the 22-29 age bracket are contacted, 246 respond and 32 refuse to respond. Assume that 1 of the 356 people is randomly selected. Find the probability of getting someone in the 22-29 age bracket or someone who agreed to respond.

Report the answer as a percent rounded to one decimal place accuracy. You need not enter the "%" symbol.

P(22-29 or agreed) =

Answer 1

I like to think of the "or" to indicate the additive property of probability, whereas "and" indicates the multiplicative property. The formula for the additive property is P(22-29 or agreed) = P(22-29) + P(Agreed) - P(22-29 and Agreed). I hope this helps!