A statistical analysis of 1,000 long-distance telephone calls made from the headquarters of the Bricks and Clicks Computer Corporation indicates that the length of these calls is normally distributed, with μ = 240 seconds and σ = 40 seconds.
a. What is the probability that a call lasted less than 180 seconds?
b. What is the probability that a call lasted between 180 and 300 seconds?
c. What is the probability that a call lasted between 110 and 180 seconds?
d. 1% of all calls will last less than how many seconds?