Sunday, June 04, 2006

Rainer's Growing Post ( 4 )

------Questions for June 6th------
1. Formulas. We've learned how to write algebraic equations in the form of mx + b = y. Convert these two sentences into algebraic equations using the above formula.
m - coefficient ( change )
x - variable
b - constant ( start )
y - solution
Sentence 1. Scott is 2 years older than Donald who turns 12 on June 21st, 2006. Write this sentence in the format of mx + b = y, then convert it into an expression which allows us to figure out the age of Scott.
D + 2 = S
D is Donald's age.
S is Scott's age.
The equation represents that Donald's age plus 2 gives you Scott's age.
Right now Donald is 11 years old.
11 + 2 = S
11 = S
Scott is 13 years old.
Sentence 2. Elizabeth has $200 in her savings account. She makes $40 every two weeks babysitting for her next door neighbours. If Elizabeth saves all of her money solve for how much money she will have in one year?
40x + 200 = y
40 is the coefficient or how much the change of her savings account every two weeks.
x is our variable. In this question it represent how many 2 weeks.
200 is the constant. It's the amount of money she already have.
1 year has 12 months and each month has about 4 weeks in it. So every month has 2 two weeks.
12(2) = 24
Now our variable represent 24.
40x + 200 = y
40(24) + 200 = y
960 + 200 = y
1160 = y
She will have $1160 in her account in one year.
2. Creation. You need to create two questions for your classmates that cover different concepts ( ex: T-charts, patterns, equations, graphs etc. ) that you have learned in this unit on algebra. You then need to show how to solve the questions.
Question 1. You are in your school's bake sale. A small pie costs $5.00, a medium pie costs $7.50 and a large pie cost $10.00. You planned to buy one medium and large and as many small ones as you can. You have $50.00. How many small pies can you buy if you are also buying 1 large and 1 medium?
The graph shows that you can buy 8 small pies if you are also buying 1 medium pie and 1 large pie.
Question 2. You have $10.00. Every week you earn $50.00 for working and spends $10.oo for shopping. How much money would you have in six weeks?
Every week you earn 50 and loses 10.
(50 + 10)x + 10 = y
So 50 - 10 = 40. Every week you earn really 40.
So our expression is 40x + 10. x is our variable. For this question it is the number of weeks.
Each month has about 4 weeks. So 6(4) = 24 weeks.
Our variable represent 24 weeks.
40x + 10 = y
40(24) + 10 = y
960 + 10 = y
970 = y
In 6 months you will have $970.
3. Reflection. You need to look back at the chart that we filled out during the first day of the unit. You now need to pick one concept that you coloured yellow or red and reflect in words what new skill that you learned on this topic.
Using T-charts to create an algebraic formula.
You may know what a t-chart is in the beginning of the unit. But you might not know what an algebraic formula was. It has coefficient, variable and constant or what we used to know as start, change and variable.
This is an example of a t-chart. In the left column is the variable, x. In the right column is the solution, y.
The algebraic formula is mx + b = y.
The left side of the column is x. The right side is going to be the solution.
1x + 7 = y
Step 3 :
1(3) + 7 = y
3 + 7 = 10
The formula didn't work so minus the extra 1 in the formula.
1x + 7 - 1 = y or 1x + 6 = y
1(3) + 6 = y
3 + 6 = 9
4. Preparing for the final exam. You need to think about the year that has past in mathematics and decide which topic is your weakest, and what you need to learn during class review in order to prepare yourself for the final exam. It is not enough to say fractions, instead pick your weakest area of fractions, say the subtraction of fractions, and give an example of what you don’t understand.
Integers. Any positive or negative numbers without decimals.
Multiplying Two Negative Integers. Multiply the numbers and the symbol is always positive.
(-4)(-5) = +20
The End

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At 4:19 PM, Blogger Levi said...

Hey Rainer, I believe Donald is 11 years old. He will turn 12 on June 21st 2006 so he's still 11 right now.


At 5:05 PM, Blogger -rain- said...

txn i forgot that part

At 12:59 PM, Blogger Mr. Reece said...

You made a few small mistakes. There are 52 weeks in a year not 48. The second mistake is that your graph shows the total amount of all pies that they can purchase as if they only buy 2 pies, one medium and one large it would cost them $17.50, which is what the graph shows, so the 8 pies for under $50 is really 6 small + 1 medium + 1 large. It is still a great question though.
Your mark is 23/25


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