The student went wrong in step three. the solutions should have been -3 and 5
Answer:
3Median = Mode + 2Mean
Step-by-step explanation:
The letter C, because the pattern is this (I think):
Every two letters it states the vowels (a,e,i,o,u)
Then in between every two letters there starts a pattern of, saying the alphabet in order and saying the alphabet backwards.
In other words they merged these two lines:
A, B, C, D, E...
+
Z, Y, X, W, V...
=
A, Z, B, Y, C, X...etc.
then by adding this pattern of vowels you get:
A, Z, E, B, I, Y, O, (C), (U), (X)...
We have the mean, μ = 20 and the standard deviation, σ = 4
X ≈ N(20, 4²)
We want P(X<15)
Standardising gives
P(X<15) = P(Z<

)
P(X<15) = P(Z< -1.25) ⇒ When the value of the z-score is negative, we will read the value of z<1.25 on the z-table then subtract the answer from 1
P(X<15) = 1 - P(Z<1.25)
P(X<15) = 1 - 0.8944
P(X<15) = 0.1056
Hence, the probability that pizza takes less than 15 minutes to be delivered is 0.1056 = 10.56%