Ratios
What is a ratio?
A comparison of two quantities
What is a rate?
A ratio that compares two different kinds of quantities, usually involving time.
What is a proportional relationship?
A relationship where two quantities increase or decrease at the same rate.
Identify the independent and dependent variable.
The number of students in a class s, and the number of desk needed D.
Independent: s
Dependent: d
If there are 3 apples and 5 oranges, what is the ratio of apples to oranges?
3:5
If you travel 60 miles in 1 hour, what is your speed in miles per hour?
60 miles per hour
If the number of apples is proportional to the number of pies, and 4 apples make 1 pie, how many apples are needed for 3 pies?
12 apples
Identify the independent and dependent variable.
The number of candles on a birthday cake, c, and that person's age, a.
Independent: a
Dependent: c
Write the ratio of 8 to 12 in simplest form.
2:3
If a car uses 4 gallons of gas to travel 100 miles, what is the rate in miles per gallon?
25 miles per gallon
If a recipe is doubled, how does that affect the proportions of ingredients?
All ingredients are multiplied by 2.
Andre uses 2 scoops of lemonade mix for each batch of lemonade he makes. Write an equation that models the total scoops (s) of lemonade mix Andre uses for batches (b).
2b = s
If the ratio of boys to girls in a class is 4:5, how many boys are there if there are 20 girls?
16 Boys
A worker earns $300 for 15 hours of work. What is the rate of pay per hour?
$20 per hour
If a car travels at a constant speed, which of the following is true: the distance is proportional to time?
Yes, if speed is constant
Lana walks for 5 minutes at the start of each run. The equation that models the total amount of time Lana spends exercising (t) after running for (r) minutes is?
5+ r = t
If a recipe calls for a ratio of 2 cups of flour to 3 cups of sugar, how many cups of flour are needed for 9 cups of sugar?
6 cups of flour
If a recipe requires 3 cups of flour for every 2 cups of sugar, what is the rate of flour to sugar?
3:2
Can you give an example of a proportional relationship in everyday life?
For instance, the cost of gas is proportional to the number of gallons purchased.
Andi makes $0.25 for each bar of sap she sells. The equation that models the total amount of money Andi makes (m) after selling (b) bars of soap is?
0.25b = m