Reminder: Word Problem Stratigies (mixtures/investments)

Ok, I can see loads of people are having trouble with some of the word problems. I was having problems with the fertilizer questions until I went back in my notes and realized the antifreeze example/question we went through in class is exactly the same. Then I experimented with the other questions in the same fashion and It wasn't too hard. I'll go through the antifreeze question (that we all should have in your notes).

Ex) Antifreeze A is 18% alcohol. Antifreeze B is 10% alcohol. How many liters of each should be mixed to get 20L of a mixture of 15% alcohol?

Step 1: Create Let Statements (be specific!)
Let a = the number of liters required of the 18% solution
Let b = the number of liters required of the 10% solution

Ask yourself... "what am I solving for?"

Step 2: Create two equations with two variables in each
L1: a + b = 20
L2: 0.18a + 0.10b = 0.15(20)

The second statement is basically (based on the let statements):
type of the first solution times liters of that solution + type of the second solution times liters of that solution = type of mixture you want times liters of the solution you want.

Maybe thinking of it like that will help y'all (I'm sure that's how Mr. Max has been saying it), instead of... point eighteen times 'a' plus point ten times 'b' equals point fifteen times twenty.

Step 3: Solve
The easiest way would be to throw it in graphmatica, but I didn't have graphmatica handy so the next easiest way was within my calculator (let's just go down the line from easiest to hardest).

I'm going to isolate b (the number of liters required of the 10% solution).
L1: b = 20 - a
L2: b = (3 - 0.18a)/0.10

I got L2 this way:
0.18a + 0.10b = 0.15(20)
0.18a + 0.10b = 3
0.18a + 0.10b - 0.18a = 3 - 0.18a
0.10b/0.10 = (3 - 0.18a)/0.10
b = (3 - 0.18a)/0.10

Remember ;)
2nd, CALC, 5: (intercept), ENTER * 3

Step 4: Create a statment to summarize your answer.
In order to create 20L of 15% alcohol antifreeze, mix 12.5L of 18% with 7.5L of 10% antifreeze.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

All raw information came from our lesson in class and out of my keyboard


:)

Friday October 26th

Today Mr.Max was away, so we had Mr.Richer as a sub. Today we worked on accelerated math and on the assignment that is due on Monday.

HOMEWORK: Student Exercise Questions: Page A-8, Exercise 2, 1-3, AND Page A-9, Exercise 3, 1a-f. ALL DUE MONDAY.

How to get to the Word Problems folder:
1) go to my computer
2) then open Rsfiles
3) open the coursework folder
4) go to the math folder and open it as well
5) then go to our class which at the moment is the second folder (Applied Math 30SA-1)
6) then you should see a folder which is labelled "word problems". Open it.

How to find the Vertex of a Parabola:
1) graph the parabola on your calculator.
2) press 2nd, then Trace.
3) then choose either minimum(cup-shaped) or maximum(cap-shaped) and press enter.
4) your screen should now show you graph again. at the bottom it will be asking you to go to the left side of where you think the vertex is. Do so with your arrow keys and then slecting enter when you are on the left.
5) now it will ask you to go right of where you think the vertex is. Do this the same as step 4 except you go to the right.
6) after you've hit enter to finalize your point in step 5, you then move your cursor to where you think the vertex is and press enter.
7) the correct vertex should then appear at the bottom of the screen. It will also state whether you used maximum or minimum.

Hopefully this helps.

*Remember that you should have 25 mastered accelerated math objectives by Wednesday October 31.*

The scribe for Monday is Shure.

Why Are There Rules in Croquet?

Please post solutions below as comments, or feel free to create a post indicating your number for your team...

RM