## Sunday, November 6, 2016

### Unit Rate Word Problems-Middle School Math-

Middle School Math-Learn how to solve unit rate word problems

Transcript

Welcome to MooMooMath where we upload a new Math video everyday

In this video I would like to talk about unit rate.

Lets first go over we solve for unit rate

Step 1. Set up a proportion equal to one unit. For example:

If 8 oranges cost 40 cents, what is the cost of 1 orange?

After the proportion is set up cross multiply

Step 3. Solve for x.

Therefore,one orange equals 5 cents

Lets look at some more examples

The first example we have,

If 24 pounds of pumpkin seeds cost $18, how much does 1 pound of pumpkin seed cost?

First lets set up a proportion. 18 dollars equals 24 pounds

I will write dollars out.

I next set the fraction to one and place the same units as the original fraction.

We have 1 pound and our x will be the cost

Notice we have dollars and dollars and pounds and pounds

The next step involves cross multiplying

I end up with 24x = 18

I next isolate the x by dividing by 24

The 24's cancel out and x equals .75

What does this tell us?

Plug the x into the fraction and .75 dollars equals 1 pound.

Therefore, 1 pound of pumpkin seeds equals 1 pound

If 4 shirts at the bargain rack costs 24.24, how much does 1 shirt cost?

Again, set up a proportion.

24.24 is how much 4 shirts cost, and remember with a proportion I need the same units on the top and bottom.

The shirts match up and 1 shirt equals x dollars.

Next I cross multiply

We have 4 x equals 24.24

x will equal to 24.24 divided by 4 which equals 6.06

We can rewrite that as 1 shirt equals 6.06

Finally I have one more.

If a car travels 168 miles in 4 hours, how far does the car travel in one hour?

Place 168 which is how far it travels.

It takes 4 hours.

Set a proportion with miles on top and hours on the botom of the fraction.

Cross multiply to find the unit rate

I have 1 hour here so x will be miles

When I cross multiply I get 4x = 168

Solve for x by dividing both sides by four

x = 42, and I can rewrite that as 1 hour equals 42 miles which tells us is that the car will travel 42 miles in 1 hour.

Hope this helps with unit rate word problems.

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