7.4d Rates ,Ratios, and Percents

Front

What is a rate?

Back

A rate is a ratio that compares two different quantities, often expressed as a quantity per unit of another quantity.

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 percent?

Back

A percent is a way of expressing a number as a fraction of 100, often used to compare relative sizes.

Front

How do you calculate the unit rate?

Back

To calculate the unit rate, divide the total quantity by the number of units. For example, if a store has 120 customers in 8 hours, the unit rate is 120 ÷ 8 = 15 customers per hour.

Front

What is the formula for percent of change?

Back

Percent of change = (New Value - Original Value) / Original Value × 100.

Front

If a stereo originally priced at $360 is on sale for $200, what is the percent of change?

Back

Percent of change = (200 - 360) / 360 × 100 = -44%. The price decreased by 44%.

Front

What is the unit rate in dollars per pound if you spend $40 on 5 pounds of concrete?

Back

Unit rate = Total cost / Total weight = $40 / 5 pounds = $8 per pound.

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply and then divide. For example, if a/b = c/d, then ad = bc.

Front

If k/10 = 1/2, what is k?

Back

Cross-multiply to find k: k × 2 = 10 × 1, so k = 5.

Front

What is the relationship between rates, ratios, and percents?

Back

Rates, ratios, and percents are all ways to compare quantities. A rate is a specific type of ratio that involves time or another unit, while a percent is a ratio that compares a part to a whole.