Go Back   EcoModder Forum > Off-Topic > The Lounge
Register Now
 Register Now
 


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-21-2011, 08:19 AM   #1 (permalink)
Master EcoModder
 
Kodak's Avatar
 
Join Date: Feb 2011
Location: USA
Posts: 346

Canyon - '07 GMC Canyon 2wd regular cab
90 day: 24.95 mpg (US)
Thanks: 41
Thanked 39 Times in 24 Posts
Exact change - ecomodder math riddle

We ecomodders like to fill our gas tanks consistently to full and generally avoid pumping extra gas to round to an exact dollar amount.

Now, most probably pay with credit cards and avoid change altogether. But I had this thought the other day:

Suppose you wanted to be prepared to give the cashier exact change, but of course you don't know what the exact cost will be. For this question, forget about paper dollars; we're only concerned about coins. What coin combination would you need to satisfy any change from 1 cent to 99 cents?

What is the fewest number of coins needed to satisfy this requirement, and what are those coins?

If I was more familiar with the Euro I would try to find the Euro equivalent for this question, but I don't know too much about the increments across the pond!

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-21-2011, 08:33 AM   #2 (permalink)
Master EcoModder
 
redneck's Avatar
 
Join Date: Jun 2009
Location: SC Lowcountry
Posts: 1,795

Geo XL1 - '94 Geo Metro
Team Metro
Boat tails and more mods
90 day: 72.22 mpg (US)

Big, Bad & Flat - '01 Dodge Ram 3500 SLT
Team Cummins
90 day: 21.13 mpg (US)
Thanks: 226
Thanked 1,353 Times in 711 Posts
.

Ten coins (not using fifty-cent pieces): four pennies, two nickels, one dime, three quarters; nine coins if a fifty-cent piece replaces two of the quarters.



>
  Reply With Quote
Old 03-21-2011, 02:20 PM   #3 (permalink)
EcoModding Apprentice
 
tumnasgt's Avatar
 
Join Date: Feb 2010
Location: Wellington, NZ
Posts: 158

The Charger - '15 BMW i3
Thanks: 81
Thanked 15 Times in 12 Posts
In New Zealand you'd need 1 10c, 2 20c, 1 50c (10c is the smallest). And if you wanted to have it for up to $5 (smallest bill), you would also need 2 $2 coins and a $1 coin.
__________________
  Reply With Quote
Old 03-21-2011, 02:32 PM   #4 (permalink)
Eco-ventor
 
jakobnev's Avatar
 
Join Date: Oct 2010
Location: sweden
Posts: 1,630

Princess - '92 Mazda MX-3 GS
House of Tudor
Team Mazda
90 day: 53.54 mpg (US)

Shirubāarō (*´ω`*) - '05 Toyota Prius Executive
Team Toyota
90 day: 54.88 mpg (US)

Blue Thunder - '20 Hyundai IONIQ Trend PHEV
Team Hyundai
Plug-in Hybrids
90 day: 587.16 mpg (US)
Thanks: 74
Thanked 701 Times in 444 Posts
Send a message via MSN to jakobnev
I'd just use one of my adjustable coins that let me set the value from 1c to 99c with a little knob.
__________________




2016: 128.75L for 1875.00km => 6.87L/100km (34.3MPG US)
2017: 209.14L for 4244.00km => 4.93L/100km (47.7MPG US)
  Reply With Quote
The Following 2 Users Say Thank You to jakobnev For This Useful Post:
Piwoslaw (03-24-2011), roflwaffle (03-21-2011)
Old 03-21-2011, 04:04 PM   #5 (permalink)
Master EcoModder
 
Kodak's Avatar
 
Join Date: Feb 2011
Location: USA
Posts: 346

Canyon - '07 GMC Canyon 2wd regular cab
90 day: 24.95 mpg (US)
Thanks: 41
Thanked 39 Times in 24 Posts
Quote:
Originally Posted by redneck View Post
.

Ten coins (not using fifty-cent pieces): four pennies, two nickels, one dime, three quarters; nine coins if a fifty-cent piece replaces two of the quarters.

>
I have to be honest here. You beat me.

For some reason, I was set on using 2 quarters instead of 3 (resulting in extra dimes). Well done. The 50 cent piece was a nice surprise.
  Reply With Quote
Old 03-21-2011, 07:52 PM   #6 (permalink)
...beats walking...
 
Join Date: Jul 2009
Location: .
Posts: 6,190
Thanks: 179
Thanked 1,525 Times in 1,126 Posts
...all the above is negated (but certainly NOT improved upon) by use of appropriate plastic.
  Reply With Quote
Old 03-24-2011, 02:02 PM   #7 (permalink)
Making Ecomods a G thing
 
Join Date: Jan 2011
Location: Illinois
Posts: 655

Angie - '08 Infiniti G35 X
90 day: 22.03 mpg (US)
Thanks: 35
Thanked 75 Times in 58 Posts
how about sitting in the parking lot and taking a few minutes to calculate the price, then go in and prepay(plus a dollar to ensure you fill the tank), and see how close you come? that could be fun, especially if you tell the cashier you'll get a dollar in change and you're correct
__________________

  Reply With Quote
Old 03-24-2011, 03:09 PM   #8 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,691

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,268
Thanked 721 Times in 458 Posts
One (1) coin and no change: Pay with a silver dollar and drop the change in the "Tips" jar.

Not as good as jakobnev, though
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell


[Old] Piwoslaw's Peugeot 307sw modding thread
  Reply With Quote
Old 03-31-2011, 05:12 PM   #9 (permalink)
EcoModding Apprentice
 
Join Date: Feb 2009
Location: UK
Posts: 162
Thanks: 2
Thanked 2 Times in 2 Posts
I dont know about anybody else, but i generally know when ill have to fill up with fuel before i set off (ie: about 1/4 tank left) so i quickly check how much change - in coins / notes - i have. When i fill up, i dont go over the amount i have in change. Simple.

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com