Do you have a typo?
Besides that, is this problem a multiple choice question
4 3/4 - 2/5
Find a common denominator
4 15/20 - 8/20
Solve
4 7/20
The plank is 4 and 7/20 feet long now.
For each answer, we can plug in the given points:
A) is technically the same as B), but B) expresses correct function notation.
B) 5 = 5(1)
⇒ 5 = 5
25 = 5(2) ⇒ 25 ≠ 10
B) is incorrect.
C) I'm not sure what you mean y=5^5=x, but I'm going to use

because it's close to what you wrote:

The function

works for the points given.
D) 5 = 1 + 5 ⇒ 5 ≠ 6
D) is not correct.
Please check your functions; I'm not sure that C) is a function. In any case, the answer is C) because all the other answers are wrong.
The corresponding z score for speed of 62 mph, 47 mph, and 56 mph is 1.5, -2.25 and 0 respectively.
<h3>
Z score</h3>
Z score is used to determine by how many standard deviations the raw score is above or below the mean. It is given by:

Where x is raw score, μ is mean, σ is standard deviation
Given that:
σ = 4, μ = 56, hence
for x = 62:

for x = 47:

for x = 56:

The corresponding z score for speed of 62 mph, 47 mph, and 56 mph is 1.5, -2.25 and 0 respectively.
Find out more on Z score at: brainly.com/question/25638875