Y varies x
Invite the constant
y = kx
Kx/x = y/x
K = y/x
Slot in the values
K = 35/140
= 1/4 or 0.25
What is the value of y when x=70
y=kx
y = 35/140 x 70/1
y = 35/2
y = 17 1/2 or 17.5
Once cross multiplied you end up with this:
15x+75=20x−30
Next subtract 20x from both sides.
15x+75−20x=20x−30−20x
−5x+75=−30 -----------> Answer
Now subtract 75 from both sides
−5x+75−75=−30−75
−5x=−105
Now divide by -5 on both sides.
-5/-5x = -105/-5
<h3 /><h3>
x = 21 --------------> ANSWER</h3>
2(x - 5) = 110
2x - 10 = 110
Add 10 to both sides.
2x = 120
Divide by 2 on both sides.
x = 60
To do that you'll need the mean and standard deviation of all the scores. Can you provide this info?
For example: Supposing that the mean of these scores were 52 and the standard deviation 3. You'd need to find the "z-score" of 57 in this case.
57 - 52
It is z = ------------ , or z = 5/3, or z = 1.67.
3
Find the area to the left of z = 1.67. Multiply that area by 100% to find the percentile rank of the score 57.
Answer: 4.7 is 10 as much as the number 0.47.
If you multiply 0.47 x 10 it will equal 4.7
