Quick Math Homework Help

Savanna listened to 6 songs in 24 minutes on her iPod. How long was one song?

A 7th grade class went on a field trip. There were 144 students on 4 buses. How many students would be on one bus?

If 8 oranges cost 40 cents, how much does it cost for one orange?

Follow these steps in order to solve **unit rate **problems.

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

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

Step 2. Cross multiply

Step 3. Solve for x

40 = 8x

40/8 = 8x/8

5 = x cents

Transcript

Unit Rate

Hi Welcome to MooMooMath. Today we are going to talk about Unit Rate or the cost of one item. So here is our example. If 8 oranges cost 240 what is the cost of one orange? 8 is to 240 as 1 is to X then solve with a cross product 8X equals 2.40, divide both sides by 8 so X is ,30 or 30 cents. Now let’s slow it down look at the rules and rework the problem. Here are the rules for finding a unit rate. First we will set up a proportion and that proportion will be set equal to the unit being one unit. Because you are trying to find the cost of one item. Then you will solve that proportion and the steps for solving a proportion are in another video, but you do a cross product, set those two equal to each other and then you divide by the coefficient. So let’s go back and rework this problem in slow motion. We have 8 oranges at a cost of 2 dollars and 40 cents. So let’s set up our proportion. 8 over 2.40 now we want to know the cost of one orange The oranges are on top so that is where our 1 is going to go because we need to know the cost of one orange, and we don’t know the cost of it so that is our variable X now we solve the cross product 8X and this cross product is very easy 240 times 1 is just 240 and then divide by the coefficient to get x by itself so x is equal to 240 divided by x or .30 which is 30 cents. So our unit cost is 30 cents an orange Hope this was helpful.

John went to the market to buy apples. The sign said “Apples - $1.23 for three apples.” At this rate, what is the cost of one apple?

Unit rate problems involve finding the cost of a single item or unit. Unit rate is a ratio containing two measurements in which the second item is one. It describes how many units of an item; correspond with one unit of the second item. Some examples include, wages per week, cost per item, and kilometers per hour.

John received his check for $150.00 for 30 hours work, and wants to know how much he earns per hour.

Set up a proportion. Remember that the denominator and numerator should be the same unit for each fraction.

Cross multiply

30x = 150

Divide each side by 30

30x/30 = 150/30

x = 5.00

John makes $ 5.00 per hour.

Mr. B. teaches 175 students in 5 classes during the day. He wants to put an equal number in each class. How many students should there be in each class?

Set up a proportion with the same units in both fractions.

Cross multiply

175 = 5x

Divide each side by 5

175/5 = 5x/5

35 = x

For equal classes each should have 35 students.