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## Pre-algebra

# Rate review

Review the basics of rates and try some practice problems.

## What is a rate?

A

**rate**is a ratio that compares two quantities with different units of measure.**Example of a rate:**

A plane flew $765$ kilometers in $3$ hours.

### Unit rates

A ${1}$ unit of the second quantity.

**unit rate**of two quantities in a ratio is the number of units of the first quantity for every**Examples of unit rates:**

There are $60$ minutes in ${1}$ hour.

Jen types $42$ words in ${1}$ minute.

*Want to learn more about rates? Check out this video.*

## Finding unit rates

To find a unit rate, we divide the first quantity in a rate by the second.

**Example:**

A plane flew $765$ kilometers in $3$ hours.

The plane flew at a rate of $255$ kilometers per hour. We can also write the unit rate as $255\text{km}:{1}\text{hour}$ .

*Want to learn more about solving unit rates? Check out this video.*

## Using unit rates to solve rate problems

Let's look at an example.

Mark can make ${42}$ birthday cakes in ${7}$ days.

**How many birthday cakes can Mark make in**${5}$ days?

First, we find the unit rate.

Days | Cakes |
---|---|

Mark makes cakes at a unit rate of $6$ cakes for every $1$ day.

Now, we can use the unit rate to find how many cakes Mark makes in ${5}$ days.

Days | Cakes |
---|---|

**In**${5}$ days, Mark can make ${30}$ cakes.

## Want to join the conversation?

- Who else finds math confusing? TwT(205 votes)
- I see it as a little confusing but once you figure it out then its really straight forward from there.(37 votes)

- If I have 5 goldfish, and my grandma eats one, then I go fishing and somehow find 10 in a river, then my sister takes 2 of them and practices animal CPR on them, I go back to the pet store and buy 53 more, then buy 89 more. How much do i spend if each goldfish is 67 cents?(76 votes)
- I think the cost is 257.18 dollars from getting all the goldfish and multiplying it by 1.67 I do not know if this is correct though(21 votes)

- like if you hate math(88 votes)
- Looks like u got a like from meh :>(7 votes)

- What are ratios?(16 votes)
- A ratio is comparing two unlike things. They are a different form of fractions.(30 votes)

- how can i find rates easier(19 votes)
- maybe work on dividing skills? i think. it seems like finding rates is similar to division in a sense(15 votes)

- Help pls I don’t understand rates but ratios I do(18 votes)
- Are you confused about the unit rate section? If so then the unit rate is when you try to find out how much it would be for only one item. This is credited to my teacher since I completely forgot lol(12 votes)

- here's a quick tip

Divide

Multiply

and Subtract

Bring it on down then bring it on back

that's all a Dividing method(20 votes)- Divide

Subtract

Multiply

Bring down

Repeat(6 votes)

- how do ya'll like math. It is unbearably hard, and I'm basically failing in it.(14 votes)
- So i'm kind of confused and I know this isn't a part of this thing but technically fractions are ratios so why do we use them as parts of things??(5 votes)
- Ratios are not the same as fractions. Ratios compare two numbers. For example if a bus goes 10 miles every 2 hours, it could be expressed as 10 miles:2 hours. You could also say that the bus is going 5 miles every hour, 5 miles:1 hour. In this case you divided both sides by 2. This is one way fractions and ratios are similar. However they are not the same, because a fraction is simply some number divided by another number. A ratio is a relationship between two numbers.(14 votes)

- i need help i dont understand this rates(6 votes)
- Rates just tell you that how one quantity relates to another quantity.For example- i read 20 pages in 5 minutes(if i am reading at a constant rate) and this can be represented as 20pages/5minutes which can be simlified to give 4pages/1minute.(9 votes)