The Owner of Touchdown Sports Bar Wants to Develop a Time

Multiple Choice

The owner of Touchdown Sports Bar wants to develop a time standard for the task of mixing a specialty cocktail. In a preliminary study, he observed one of his bartenders perform this task seven times with an average of 90 seconds and a standard deviation of five seconds.
What is the standard time for this task if the bartender worked at a 20 percent faster pace than is average, and an allowance of 20 percent of the workday is used?

A)  112.5 seconds
B)  120 seconds
C)  135 seconds
D)  144 seconds
E)  150 seconds