Answer:
Standard time = 118.8 second
Explanation:
given data
observed time = 90 seconds
Allowance factor = 10% = 0.10
standard deviation = 5 seconds
bartender worked = 20 percent
solution
we get here average observed time that is express as
average observed time = 90 × 1.20
average observed time = 108 seconds
and standard time for the task that is express as
Standard time = Average observed time × (1 + Allowance factor)
Standard time = 108 × (1 + 0.10)
Standard time = 108 × 1.10
Standard time = 118.8 second