All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Getting gadgets galore (Posted on 2011-12-12) Difficulty: 1 of 5
To buy a certain gadget you need at least four US coins,- two similar gadgets require no less than six coins while for a purchase of three only two coins are needed.
What minimal price of the said item fits the description above?

Rem: The coins denominations are 1,5,10,25,50,100 cents .

No Solution Yet Submitted by Ady TZIDON    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Makes cents (spoiler) | Comment 1 of 3
Consider first buying 3 items with two coins.  The two coins must sum to a multiple of 3, so the three must cost either 6, 15, 30, 51, 60, 75, 105 or 150 cents.

That makes one gadget either 2,5,10,17,20,25,35 or 50 cents.

Only 17 cents requires more than two coins, so that is our solution. It is not only minimal, it is unique.

Just as a check, two gadgets costs 34 cents, which requires at least 6 coins.

  Posted by Steve Herman on 2011-12-12 11:13:09
Please log in:
Remember me:
Sign up! | Forgot password

Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Copyright © 2002 - 2018 by Animus Pactum Consulting. All rights reserved. Privacy Information