Phone | ||
---|---|---|
Dinner dance | 55% | 80% |
Football game | 20% | 10% |
Picnic | 20% | 5% |
Pool party | 5% | 5% |
Total | 100% | 100% |
The correct answer is . It’s given that the number of email responses is twice the number of phone responses. Therefore, if the number of phone responses is p, then the number of email responses is
. The table shows that 20% of people who responded by phone preferred a picnic. It follows that the expression
represents the number of these people. The table also shows that 5% of the people who responded by email preferred a picnic. The expression
, or
, represents the number of these people. Therefore, a total of
, or
people preferred a picnic. Thus, the probability of selecting at random a person who responded by email from the people who preferred a picnic is
, or
. Note that 1/3, .3333, and 0.333 are examples of ways to enter a correct answer.