Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15. find the probability that a randomly selected adult has an IQ between 89 and 111.

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.