The Bar of Gold
Math brain teasers require computations to solve.
A worker is to perform work for you for seven straight days. In return for his work, you will pay him 1/7th of a bar of gold per day. The worker requires a daily payment of 1/7th of the bar of gold. What and where are the fewest number of cuts to the bar of gold that will allow you to pay him 1/7th each day?
HintOnly two cuts are required.
Day One: You make your first cut at the 1/7th mark and give that to the worker.
Day Two: You cut 2/7ths and pay that to the worker and receive the original 1/7th in change.
Day three: You give the worker the 1/7th you received as change on the previous day.
Day four: You give the worker 4/7ths and he returns his 1/7th cut and his 2/7th cut as change.
Day Five: You give the worker back the 1/7th cut of gold.
Day Six: You give the worker the 2/7th cut and receive the 1/7th cut back in change.
Day Seven: You pay the worker his final 1/7th.
Everyone is happy.
Apr 02, 2002
|awesome teaser... had to look at the answer|
Apr 03, 2002
|I agree! This is a new favorite of mine.|
Apr 04, 2002
Apr 11, 2002
|Awesome??? Use your brains...the assumption is that the worker will give you the gold you have already cut. However, since he "requires payment everyday" there might be some reason to suspect that he might have already spent it? |
Mar 06, 2004
Nov 29, 2004
|Wow.... I thought this was going to be some stupid trick answer lol.. but that's awesome! You had me stumped... |
Nice teaser... my first favorite lol
Nov 29, 2004
|Am I missing something? Can you pay in advance? Cut the bar 0 times?|
Nov 29, 2004
|That would require just 2 cuts: one at 1/7, leaving 6/7 of the bar. Another one at 2/7, leaving 4/7 of the bar. With these 2, you have to pay all days. Funny thinking. |
I didn't take into account that the worker will keep the part of gold you gave to him (there must be a reason why the worker needs a daily pay).
So, If the worker spends his gold everyday, your "give back" trick doesn't work. In that case, you will need 4 cuts to accomplish the payment: First day you cut 1/7, leaving 6/7 fo the bar. The next day you do 1 cut longwise and then 2 cuts one third of the bar, leaving 6 equally sized chunks, the pay for the next 6 days.
Anyway to make it smaller?
Nov 29, 2004
|This is one of those brain teasers that makes you kick yourself for not getting it right the first time. It's all about going past black and white and looking at the gray. Loved it.|
Alan - Nashville
Nov 30, 2004
|That was the dumbest riddle ever!!!! Why would u do that? Who's responsible 4 this? |
Dec 01, 2004
|Not only is this a great teaser, it is actually a clever and practical answer. Who’s going to pay the whole bar up front? You would never see the guy again. The worker ain’t going to trust you to pay up on completion, too many bad debtors around. He may not want to spend the gold every day but he wants to make sure he’s had a daily payment. Each cut will waste gold, lost in dust in the saw and air. Actually it depends on the dimensions of the bar as to where you make the cuts. If the bar was 7x4 for example, first cut at 3/7ths mark leaving 4x4 square and 3x4 rectangle. Cut the seventh from the 3x4 across the shorter dimension which is 25 percent shorter cut than cutting the seventh from the original bar. |
Feb 26, 2005
|Ummm. Okay. Didn't appreciate the problem much though. I bet its just me.|
Mar 10, 2006
|Then again, who pays wages in gold bars?|
Jun 21, 2007
|Its kinda tricky and hard but still is good! I thought that in the 7th day you just give the worker a whole bar of gold! lol |
Jan 02, 2009
|Very clever! First teaser in a long time that I didn't get right. |
Mar 24, 2010
|Clever indeed but not for the worker. This worker has been cheated. Where on Earth would you find a worker wanting to get paid on a daily basis and not using his wages. If he keeps on giving his 1/7th back then he's being cheated. At the end of the 7th day he would only have received 3/7th of his wages. [He received 2/7th on the 6th day and another 1/7th on the 7th day.] Nice teaser but not practical. Anyone else sees this???????|
Sep 14, 2011
| nice!!! |
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