Math Topics, Problem Solutions and Teaching Ideas: 2013

Saturday, November 30, 2013

Which Discount is Best?

%%%% SALE %%%% DISCOUNT %%%% SAVE %%%%
When we buy an item "ON SALE" and the store gives
us a discount, say 25% (25% OFF), there are two ways
to find the FINAL PRICE.
I) Multiply the Original (LIST) Price by .25
and then subtract this number (25% of the List Price)
from the LIST PRICE. (Thus, using two steps.)
II) A one step process of Multiply the ORIGINAL PRICE
by .75 and having this product be the Final Price.
*******************************************
With the above explanation, try this puzzle:

Which of the following two options would
save the most money?
Option #1: You can buy a $90.00
pair of shoes with a single discount of 29%.
OR
Option #2: The same pair of shoes can have
SUCCESSIVE DISCOUNTS of 10% and then 20%.

Try making you decision without performing
any arithmetic calculations.
After you make your choice, then actually
find the Final Prices under each Option.
*******************************************
AFTER YOU HAVE ATTEMPTED THIS PUZZLE,
you can view the solution by copying the yellow region below.
*************SOLUTION***************
You were probably surprised to find that
the one 29% discount was the best!

A more Algebraic explanation follows:

Let the LIST PRICE be represented by N.
The first of two discounts,10% off,
can be found by taking the
LIST PRICE TIMES .9 -> .9(N)
Multiplying this .9(N) times .8 results in
(.8)(.9)(N) or (.72)(N)
This is equivalent to an 28% Discount.
*************SOLUTION***************

Wednesday, March 20, 2013

Animated Whiteboard Presentations

MEAN, MEDIAN and MODE

Please click on video to enlarge!

(Mean Median Mode)

To see a larger view of the video,
Click on the BOTTOM RIGHT CORNER.
The video will FILL THE SCREEN.
To get BACK to the SMALLER VIEW
HIT the "ESC" button on your keyboard