Answer:
The frequency distribution is given below:
Class Frequency
0 - 9 9
10 - 19 6
20 - 29 3
30 - 39 3
40 - 49 3
From the given 4 options, the histogram in option A accurately displays this data. Hence the option A is correct.
Answer:
a) Therefore 92.64% of customers receive the service for half-price.
b) Therefore it would take 8.52 minutes
Step-by-step explanation:
Given that ime required for an automotive center to complete an oil change service on an automobile approximately follows a normal distribution with:
mean (μ) = 15 minutes
Standard deviation (σ) = 3.5 minutes
a) The z score is given by the equation:

Since the service will take no longer than 20 minutes,

Using the probability table to get the probability of the z score
percent of customers receive the service for half-price = P(X < 20) = P(z < 1.43) = 0.9236 = 92.64%
Therefore 92.64% of customers receive the service for half-price.
b) Since the probability is 3% = 0.03, this corresponds with a z score of -1.88
Therefore:



Therefore it would take 8.52 minutes
The percent of n is bye bye
Area of ABC : AB*AC/2
the maximum of the parabola is reached at x=-4/(2*(-1))=2 hence A is at (2,0) and B is at (2,(-2)^2+4*2+C)=(2,12+C)
C is the second root (x-intersect), which we can find :
determinant1 : D=16-4*(-1)*C=4(4+C) thus the second root is at x=

Hence the area of the triangle is

hence

.
We remark that

Hence 4+C=16 thus
C=12