Answer:
38.11%
Step-by-step explanation:
Given that:
Mean (μ) = 75, standard deviation (σ) = 5
Z score is a measure in statistics to determine the variation of a raw score from the mean. It is given by the equation:

To calculate the percentage of students scored between a 73 and 78 (C grade), we need to find the z score for 73 and then for 78.
For x = 73, the z score is:

For x = 78, the z score is:

From the probability distribution table:
P(73 < x < 78) = P(-0.4 < z < 0.6) = P(z < 0.6) - P(z < -0.4) = 0.7257 - 0.3446 = 0.3811 = 38.11%
As you know 30/45 = 6/9
So a = 9 makes the equation true
Answer:
B. 10
Step-by-step explanation:
Look at the chart.
Find how many members are 50-60 inches tall. (6)
Find how many members are 61-70 inches tall. (4)
Add each member count up. (10)
Answer:
She will save $5.25
Step-by-step explanation:
21 x 25% = 5.25
If you multiply 36 by four since there are 4 wheels for skateboard
you will get 144. That number is the total number of wheels you need to order and since they come in packs of 20 what you need to do is divide 144 by 20 and you will get 7.2. So obviously you can't order 7.20 packs of wheels so this means that 8 packs of wheels must be bought in order to ensure that all of the skateboards get wheels on them.
The answer is 8.