4. Unit rate of each item (It is asking you what the price is for 1 of the items)
There are two methods of solving the fourth question. I will solve the first question with method 1 the second with method 2 and the third you can do on your own using which ever method you like the best
box of 4 light bulbs costs $3.79
Method 1: Make a proportion where it is
For the fraction on the left side of the equation put what is given to you in the question:
In the numerator (top number of fraction) the 4 goes, because there are four lightbulbs
In the denominator (bottom number of fraction) the 3.79 goes, since that is the price of 4 lightbulbs
In the second fraction, on the right side of the equal sign:
In the numerator put 1, because we are trying to solve how much 1 lightbulb costs
We don't know how much one lightbulb costs, since this is what we are solving for, so you put an x in the denominator of the second fraction.
This is how your proportion should look like:
Now you must solve for x (the price of 1 light bulb). To do this you can cross multiply (aka the butterfly). If you don't know what that is the image of an example bellow (note! this is not the proportion from this question just an example of what cross multiplying is)
4x = 3.79
Now isolate x. To do this you must divide 4 to both sides ( division is the opposite of multiplication and will cancel the 4 out from the left side)
4x / 4 = 3.79 / 4
x = 0.95 <<<This is an estimate since it asked to round to the nearest cent . The original answer is .9475, so I just rounded it
^^^To check this you must simply multiply this number by 4
.95 x 4 = 3.80 <<<Remember: we rounded .95. This is a rough estimate. If your multiply .9475 by 4 then you get exactly 3.79
A bag of 5 oranges costs $2.19
Method 2: This is much quicker and the method that I prefer.
All you have to do is divide 2.19 by 5 this will get you how much 1 orange costs (Cost always comes before the amount when you are dividing ie: 2.19 is the cost and 5 apples is the amount)
2 .19 ÷ 5 = 0.438 ≈ 0.44
Check by multiplying .44 by 5
5. For this one you do the same process as above. First you have to find how much Melody gets payed per hour. When she works 3 hours she gets $19.50. This means you have to divide 19.50 by 3 (remember: cost/amount... In this case its: payed/hours. same thing)
19.50 ÷ 3 = 6.50
Per hour she gets payed $6.50. This means that per half hour (or .5 of an hour) she gets payed $3.25 (divide 6.50 by 2. This will split the hour in two 30 min/.5 of an hour).
For the chart (only for 2.5):
Melody works 2 full hours and .5 of an hour (30 min). This means that she earned $6.5 x 2. Which equals 13. She also worked a half hour, which is 3.25 per half hour. To find the total pay she gets for 2.5 hrs add $13 plus 3.25, which is $16.25 in 2.5 hrs
For the 5 hrs just multiply 13 by 5
Hope this helped and makes sense!