Review of ratios, rates and better buy

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 different units, such as speed (miles per hour) or price per item.

Front

What is a unit rate?

Back

A unit rate is a rate in which the second quantity is one unit. For example, if there are 29 students per class, the unit rate is 29 students per 1 class.

Front

How do you calculate a unit rate?

Back

To calculate a unit rate, divide the first quantity by the second quantity, ensuring the second quantity equals one.

Front

What is the formula for finding the better buy?

Back

To find the better buy, calculate the unit price (cost per unit) for each option and compare them.

Front

If a pack of 12 juice boxes costs $6.59, what is the unit price?

Back

The unit price is calculated as follows: $$\frac{6.59}{12} = 0.5492$$, so approximately $0.55 per juice box.

Front

If Crayola crayons cost $6.97 for 120 crayons, what is the unit price?

Back

The unit price is calculated as follows: $$\frac{6.97}{120} = 0.0581$$, so approximately $0.06 per crayon.

Front

Which is the better deal: $2.98 for 15 oz of Oreos or $2.50 for 14 oz of Chips Ahoy?

Back

Calculate the unit prices: Oreos: $$\frac{2.98}{15} \approx 0.1987$$ per oz; Chips Ahoy: $$\frac{2.50}{14} \approx 0.1786$$ per oz. Chips Ahoy is the better deal.

Front

What is the unit price of Coca-Cola if it costs $1.29 for 1.25 L?

Back

The unit price is calculated as follows: $$\frac{1.29}{1.25} = 1.032$$, so approximately $1.03 per liter.

Front

What is the unit price of Pepsi if it costs $2.49 for 2 L?

Back

The unit price is calculated as follows: $$\frac{2.49}{2} = 1.245$$, so approximately $1.25 per liter.