February 2012
Problem of the Month

Armadillo Restaurant Problem



Last Fall, the Armadillo Restaurant in Fort Collins sent me the following coupons:
(1) $10 off any purchase of $35 or more,
(2) 25% off the total bill, and
(3) Buy one entree and get the second one free ($10 value).




(A) Explain which coupon I should use to maximize my savings.   Give all possibilities.

(B) What total purchase would result in the same savings with all three coupons?



Solution to the Problem:

(A)
Use coupon #3 for any bill up to $35.

Use either coupon #1 or coupon #3 for any bill from $35 to $39.99.

Use any of the coupons for a $40 purchase.

Use coupon #2 for all bills over $40.

(B)
All three coupons will save you $10 on a $40 bill.

The chart helps to see why you should use which coupon.
It shows the savings with each coupon for various bills.

If bill is:   Coupon #1   Coupon #2   Coupon #3  
$0 - $20 NONE $0 - $5 $0 - $10
$20 - $35 NONE $5 - $8.75 $10
$35 - $40 $10 $8.75 - $10 $10
$40 $10 $10 $10
$40 - $100 $10 $10 - $25 $10




Correctly solved by:

1. James Alarie Flint, Michigan
2. Holden Bindl Mountain View High School,
Mountain View, Wyoming
3. Chad Fore Gate City, Virginia


Send any comments or questions to: David Pleacher