Answer:
59.48%
Step-by-step explanation:
To determine the probability you have to calculate the z score which is equivalent to the number of standard deviations you are from the mean.
[tex]z = \frac{x-\mu}{\sigma}[/tex]
x is the value you want to know its probability
μ is the mean
σ is the standard deviation
[tex]z = \frac{12-12.6}{2.5} =-0.24[/tex]
A z score of -0.24 means you are 0.24 standard deviation at the left of the mean, the probability associated to a z of -0.24 can be found in a z table and it is 40.52%.
That probability cover the minimum value until 12 minutes, so the probability to need more than 12 minutes is 100 - 40.52 = 59.48%
