PSAT Math Grid-Ins Question 12: Answer and Explanation

Question: 12

Estimated Numbers of Cell Phone Users by Type (in millions)

If a cell phone user is selected at random in 2008, what is the probability that user is a contracted user?

Correct Answer: 5/6

Explanation:

The question asks for a probability, which is defined as . Read the table carefully to find the right numbers. The question asks for the probability that a cell phone user in 2008 is a contracted user, so look at the row labeled 2008. In 2008, there were 225 contracted users, so that is the number of outcomes you want. There were 270 total cell phone users in 2008, so that is the number of possible outcomes. Therefore, the probability is . Reduce the fraction to get , or express it as a decimal, which is 0.833. Grid in either the fraction or the decimal. When gridding in a repeating decimal, remember to include as many places as will fit, so grid in 0.833. The correct answer is or .833.