Answer:
18.165%
Explanation:
We solve this question using z score formula
z = (x-μ)/σ
From the Question above , we are asked to find the percent of the class that will fail if the passing grade is 54.
The percent of the class that would fail is the percent of the class that has a grade less than(<) 54
Hence,
x is the raw score = 54
μ is the population mean = 64
σ is the population standard deviation = 11
For x < 11
z = 54 - 64/11
z = -0.90909
Probability value from Z-Table:
P(x<54) = 0.18165
Converting to percentage
= 0.18165 × 100
= 18.165%
Therefore, If the passing grade is 54, the percent of the class that will fail is 18.165%