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 10 percent of job time is used?

A)  135 seconds
B)  123.8 seconds
C)  118.8 seconds
D)  120 seconds
E)  112.5 seconds