Answer:
(i) She gives each student a pretest. Then she teaches a lesson using a computer program. Afterwards, she gives each student a posttest. The teacher wants to see if the difference in scores will show an improvement.
Step-by- Step
The situation is a case of matched or paired samples since the samples are dependent. The two measurements are drawn from the same pair of individuals The parameter that is tested using matched pairs is the population mean and this is what teacher intends to use a hypothesis test for.
Part I
We have the size of the sheet of cardboard and we'll use the variable "x" to represent the length of the cuts. For any given cut, the available distance is reduced by twice the length of the cut. So we can create the following equations for length, width, and height.
width: w = 12 - 2x
length: l = 18 - 2x
height: h = x
Part II
v = l * w * h
v = (18 - 2x)(12 - 2x)x
v = (216 - 36x - 24x + 4x^2)x
v = (216 - 60x + 4x^2)x
v = 216x - 60x^2 + 4x^3
v = 4x^3 - 60x^2 + 216x
Part III
The length of the cut has to be greater than 0 and less than half the length of the smallest dimension of the cardboard (after all, there has to be something left over after cutting out the corners). So 0 < x < 6
Let's try to figure out an x that gives a volume of 224 in^3. Since this is high school math, it's unlikely that you've been taught how to handle cubic equations, so let's instead look at integer values of x. If we use a value of 1, we get a volume of:
v = 4x^3 - 60x^2 + 216x
v = 4*1^3 - 60*1^2 + 216*1
v = 4*1 - 60*1 + 216
v = 4 - 60 + 216
v = 160
Too small, so let's try 2.
v = 4x^3 - 60x^2 + 216x
v = 4*2^3 - 60*2^2 + 216*2
v = 4*8 - 60*4 + 216*2
v = 32 - 240 + 432
v = 224
And that's the desired volume.
So let's choose a value of x=2.
Reason?
It meets the inequality of 0 < x < 6 and it also gives the desired volume of 224 cubic inches.
Answer:
26
Step-by-step explanation:
When we subtract a negative it is like adding
(-16) - (-42)
(-16) + (42)
Re arranging the order
42 -16
26
Answer:
shirt = $20
sweater = $35
Step-by-step explanation:
This question would be solved using simultaneous equation
Let the price of sweater be represented by a
Let the price of shirt be represented by b
The following equations can be derived from the question
2a + 4b = 150 equation 1
4a + 3b = 200 equation 2
Multiply equation 1 by 2
4a + 8b = 300 equation 3
Subtract equation 2 from 3
5b = 100
divide both sides of the equation by 5
b = 20
substitute for b in equation 1
2a + 4(20) = 150
2a + 80 = 150
collect like terms
2a = 150 - 80
2a = 70
divide both sides by 2
a = 35
Price of sweater = $35
Price of shirt = $20
