The time taken to clean up the Mt. Etna Pizza Parlour after it closes follows a normal distribution with a mean of 30 min and a standard deviation of 5 min. What is the probability that the cleanup crew will complete the job in less than 20 min?Choose one answer. 1. 0.9772. 0.0113. 0.5004. 0.023

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SOLUTION

From the question, we will apply the Zscore formula

[tex]\begin{gathered} Z=\frac{x-\mu}{\sigma} \\ x=20,\mu=30,\sigma=5 \end{gathered}[/tex]

Applying, we have

[tex]\begin{gathered} Z=\frac{20-30}{5} \\ Z=-\frac{10}{5} \\ Z=-2 \end{gathered}[/tex]

Using the Zscore calculator, we have that

P(x<20) = 0.02275

Hence the answer is 0.023