The school store is running low on erasers for pencils. They want to order more, so they look at the prices for 4 brands. Which one is the best buy??
Brand A: 20 for $2.50
Brand B: 35 for $3.25
Brand C: 50 for $5.25
Brand D: 100 for $10.00
To find the best buy, we need to calculate the cost per eraser for each brand.
Brand A: 2.50 ÷ 20 = $0.125 per eraser
Brand B: 3.25 ÷ 35 ≈ $0.093 per eraser
Brand C: 5.25 ÷ 50 = $0.105 per eraser
Brand D: 10.00 ÷ 100 = $0.10 per eraser
Based on the calculations, Brand B is the best buy with approximately $0.093 per eraser.
If a dozen pencils cost $1.35, what is the unit cost?
$0.11
$1.23
$0.13
$0.13
$4.29
To find the unit cost, we need to divide the total cost by the quantity.
A dozen pencils is equal to 12 pencils.
So, the unit cost is: $1.35 ÷ 12 = $0.11
Therefore, the correct answer is $0.11.
Find the slope of the line given the points on the graph.
(-2, -5) (0,1)
The slope of a line can be calculated using the formula:
slope = (y2 - y1) / (x2 - x1)
In this case, the given points are (-2, -5) and (0, 1).
Using the formula, the slope is:
slope = (1 - (-5)) / (0 - (-2))
= (1 + 5) / (0 + 2)
= 6 / 2
= 3
Therefore, the slope of the line is 3.
The distance traveled in a car varies directly as the amount of gasoline used. If a car travels 640 miles and uses 32 gallons of gas, find the constant of variation or miles per gallon (mpg).
The distance traveled (in miles) varies directly with the amount of gasoline used (in gallons). This can be represented as:
miles = constant * gallons
Let's denote the constant as k. In this case, we know that when the car travels 640 miles, it uses 32 gallons of gas. Substituting these values into the equation, we get:
640 = k * 32
To find the value of k, we can divide both sides of the equation by 32:
k = 640 / 32
k = 20
Therefore, the constant of variation, or miles per gallon (mpg), is 20.
In her science classroom, Mrs. Hall noticed that the lengths (in inches) and weights (in ounces) of the class's pet ferret were directly related by the equation y = kx, where x is the length and y is the weight. Use the information in the table to find k, the constant of proportionality.
length (x):
6
9
12
15
Weight (y):
15
22.5
30
37.5
To find the constant of proportionality k, we can use any set of corresponding values for x and y from the table and apply the equation y = kx.
Let's use the first set of values x=6 and y=15:
15 = k * 6
To find k, we divide both sides of the equation by 6:
k = 15 / 6
k ≈ 2.5
Therefore, the constant of proportionality k is approximately 2.5.
Identify the unit rate on the graph.
(2,120) (3,180) (4,240)