Ratios/Rates/Proportions

Front

What is a ratio?

Back

A ratio is a comparison of two quantities by division, showing how many times one value contains or is contained within the other.

Front

What is a rate?

Back

A rate is a specific kind of ratio that compares two quantities with different units, such as speed (miles per hour) or price per item.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you find the unit rate?

Back

To find the unit rate, divide the quantity by the number of units. For example, if you have 60 miles in 3 hours, the unit rate is 60 miles ÷ 3 hours = 20 miles per hour.

Front

If a cashier rings up 2 customers in 8 minutes, how many customers can he ring up in 30 minutes?

Back

7.5 customers.

Front

How do you calculate the unit cost of an item?

Back

To calculate the unit cost, divide the total cost by the number of items. For example, if 15 pizzas cost $97.50, the unit cost is $97.50 ÷ 15 = $6.50 per pizza.

Front

What is the unit rate of customers served if a store has 120 customers in 6 hours?

Back

20 customers per hour.

Front

How do you determine which is the better buy?

Back

To determine the better buy, calculate the cost per unit for each option and compare them.

Front

If a 12-pack of soda costs $3.50, what is the cost per can?

Back

$3.50 ÷ 12 = approximately $0.29 per can.

Front

If it costs $46.80 to fill a 13-gallon gas tank, what is the price of gas per gallon?

Back

$3.60 per gallon.