3.2+Estimating+Profit+0809

John Beninger Sun,5th, April, 2009 Block: 8D **__3.2 Say it With Symbols __** -* means multiplied by -/ means divided by

A. If 40 children and 30 adults participate in the walkathon there should be $405 raised.

B. Two equivalent expressions for the total income in terms of the number of adults (a) and number of children (c) who participate could be: $1000+$5c+$15a and $1000+(c*15)+(a*15).

C. Two equivalent expressions for the total expenses in terms of adults (a) and children (c) could be: ($500+$250) +(c*$6)+(a*$8.5) and $750+$6c+$8.5a.

D. An expression to show the total profit as total income-total expenses could be: ($1000+$5c+$15a)-($750+$6c+$8.5a).

E. An expression to show the profit that is as short as possible could be: $250-$1c+$6.5a this is equivalent to the other equation as shown below above the beginning of question f:   After evaluating my profit expressions form D and E (as shown above) I can conclude that my results are equivalent since both expressions simplify to $825. G. The advantage of writing the profit expression in shorter form is that it is easier and faster to calculate The disadvantage is that you have less information about how you found your answer. __Follow Up __ 1. 5(10-2) or 8.5 are two ways to show Benjamins score on his math test were he got two of 10 questions wrong with each question being worth 5 points.

2. a: A situation that could be represented by the expression 100-(x+y) could be the amount of kitakat bars on the counter of a store with 100 being the amount of kitkat bars x being the amount of kitkat bars in the back and y being the amount of kitkat bars already sold.

b: Using the distributive property made the expression 100-x-y which is equivalent to 100-(x+y).

3.a: A situation that could be represented 50-2x-2y could be the amount of books on a shelf in the fiction section of a library with x being the average amount of books on the two bookshelves on the left of our bookshelf and y being the average amount of books on the bookshelves to the right of our bookshelf and 50 being the amount of books not checked out in the fiction section of the library.

b:Using the distributive property an equivalent expression to 50-2x-2y could be 50-((2*x)+(2*y)).

4. 3-2x and 3x-2 are not equivalent because while you can switch the position of terms around an addition sign you can’t change only part of a term.

5. a. 7x+7 b. -2x-3 c. 5r+12t+38 d. 39-12x+9x