Convenience store puzzle

[QuikSand]

So, I'm picking up a few items at my local convenience store, whose familiar name I am omitting here as a silent protest of their refusal to allow pr0n on their mag racks.


The clerk seems my four items, and announces "that will be $7.11, sir."

But then he corrects himself... "oops, I accidentally multiplied the four prices together, rather than adding them. Let me correct that."

Here you will need a massive suspension of disbelief, I understand, to imagine a convenience store clerk with both this degree of computational ability and complete lack of common sense... but it's kind of important for the puzzle...

After a short pause, he says "hey, what do you know, it still adds up to $7.11, sir."



How much did each of my four purchases cost?

[WSUCougar]

Whohoo! Cheap meat!

[PackerFanatic]

Is tax included?

[st.cronin]

I will solve this puzzle for 1 million dollars, and not a penny less.

[molson]

It's really obvious to me, but I'd like to give others a chance

[QuikSand]

Originally Posted by PackerFanatic

Is tax included?

You should ignore taxes for purposes of this puzzle.

[Bee]

Originally Posted by QuikSand

You should ignore taxes for purposes of this puzzle.

woohoo! I'm buying my xbox 360 today then!

[Passacaglia]

Was the product exactly $7.11, or $7.11 with rounding?

[Celeval]

Closest I've got is multiplying to 7.11 but adding to 7.08... still going.

[kcchief19]

I'm also assuming you're looking for exact real-life prices and not imaginary prices like $1.7489323. I can get to $7.10 quite easily.

[Passacaglia]

Originally Posted by Celeval

Closest I've got is multiplying to 7.11 but adding to 7.08... still going.

I've got adding to 7.11, but multiplying to 7.1176 -- stupid rounding.

[QuikSand]

This puzzle is solvable with ordinary two-digit prices that both multiply and add exactly to 7.11.

[rewissick]

(edit...nevermind...I'm an idiot, and the second to admit it)

[QuikSand]

Originally Posted by rewissick

Did I get it?

You may want to brush up a bit on the concept of "multiplication."

[PackerFanatic]

Hehe...

[Passacaglia]

Blah. I've got adding to 7.11, multiplying to 7.105 -- at least it rounds to 7.11!

[TredWel]

Not too proud of the solution, got it more or less through brute force, but it works!

Spoiler...





















$1.20, $1.25, $1.50, $3.16

Edit: Got to watch my grammar & spelling in Quiksand-related threads.

[Passacaglia]

Thanks for putting me out of my misery.

[rowech]

Amen...I had taken it to excel.

[rkmsuf]

Wonder what Quik bought.



Generic brand profolactics(small size) - $3.16

[bbor]

2/3

[Bee]

Originally Posted by rkmsuf

Wonder what Quik bought.



Generic brand profolactics(small size) - $3.16

pack of #2 pencils = $1.20

[dacman]

Brute force? Here's some real brute force:

#include 
int main(void)
{
 for(int a=1;a<=711;a++) {
  for (int b=1;b<=711;b++) {
   for(int c=1;c<=711;c++) {
    for(int d=1;d<=711;d++) {
     if (a+b+c+d==711){
      if (a*b*c*d==711000000) {
       printf("a= %d  b= %d  c= %d  d= %d\n",a,b,c,d);
      }
     }
    }
   }
  }
 }
 return 0;
}
 

[rkmsuf]

10 Print "dacman molests collies."
20 Goto 10

[QuikSand]

Originally Posted by rkmsuf

Wonder what Quik bought.



Generic brand profolactics(small size) - $3.16

Was this post really necessary or called for?





After all, you know how sensitive I am about... bad spelling.

[Dutch]

It's too bad this didn't happen to me. The thread title would have been totally different.

"Holy Shit! You'll never guess what happened today!!one*!!111!1!"

*subbyism

[Toddzilla]

1 pack Logarithmic Graph Paper = $1.50

[rkmsuf]

Originally Posted by QuikSand

Was this post really necessary or called for?





After all, you know how sensitive I am about... bad spelling.

I think the generic ones run big.

[Passacaglia]

Originally Posted by rkmsuf

Wonder what Quik bought.



Generic brand profolactics(small size) - $3.16

I think that's how much bibles cost.

[Pumpy Tudors]

Two pounds of cucumbers = $1.25

[rkmsuf]

So we have profolactics, cucumbers, graph paper and pencils.

*shudder*...some type of experiment....*shudder*

[Ksyrup]

Cucumbers are typically sold per cucumber, not per pound. I would expect you to know that.

They're also not usually sold at convenience stores.

[Bee]

The answer being something other than 2/3....priceless.

[QuikSand]

Back to the original puzzle - this can be solved without just brute force.

Trick is to get past the decimals, and think of the prices in pennies 9interegrs are just easier to deal with). With that in mind, the multiplied version has to take the 1/100 exchange into account four times -- meaning that the multiplied value of the four prices is going to be 7.11 expanded by eight decimal places, or rather 711,000,000.

Taking prime factors of this number, by whatever method you like, gets you to:

six iterations of 5
six iterations of 2
two iterations of 3
and 79

From there, it's a much simpler brute force application to assemble these components (multiplied into groups) that will add up to the total of 7.11:

5x3x2x2x2 = 120
5x5x5 = 125
5x5x3x2 = 150
79x2x2 = 316

120 + 125 + 150 + 316 = 711

Convert all to dollars instead of pennies, and you're done.

[Toddzilla]

Originally Posted by Passacaglia

I think that's how much bibles cost.

Snerk...

[Pumpy Tudors]

Originally Posted by Ksyrup

Cucumbers are typically sold per cucumber, not per pound. I would expect you to know that.

They're also not usually sold at convenience stores.

Apparently, I go to the wrong convenience stores.

[Ksyrup]

Originally Posted by QuikSand

Back to the original puzzle - this can be solved without just brute force.

Trick is to get past the decimals, and think of the prices in pennies 9interegrs are just easier to deal with). With that in mind, the multiplied version has to take the 1/100 exchange into account four times -- meaning that the multiplied value of the four prices is going to be 7.11 expanded by eight decimal places, or rather 711,000,000.

Taking prime factors of this number, by whatever method you like, gets you to:

six iterations of 5
six iterations of 2
two iterations of 3
and 79

From there, it's a much simpler brute force application to assemble these components (multiplied into groups) that will add up to the total of 7.11:

5x3x2x2x2 = 120
5x5x5 = 125
5x5x3x2 = 150
79x2x2 = 316

120 + 125 + 150 + 316 = 711

Convert all to dollars instead of pennies, and you're done.

I think this is as good a time to post this as any...

[st.cronin]

Originally Posted by QuikSand

Back to the original puzzle - this can be solved without just brute force.

Trick is to get past the decimals, and think of the prices in pennies 9interegrs are just easier to deal with). With that in mind, the multiplied version has to take the 1/100 exchange into account four times -- meaning that the multiplied value of the four prices is going to be 7.11 expanded by eight decimal places, or rather 711,000,000.

Taking prime factors of this number, by whatever method you like, gets you to:

six iterations of 5
six iterations of 2
two iterations of 3
and 79

From there, it's a much simpler brute force application to assemble these components (multiplied into groups) that will add up to the total of 7.11:

5x3x2x2x2 = 120
5x5x5 = 125
5x5x3x2 = 150
79x2x2 = 316

120 + 125 + 150 + 316 = 711

Convert all to dollars instead of pennies, and you're done.

I bolded the only part of this post that I understood.

[rowech]

Interesting read....I took the approach of chaning 7.11 to an improper fraction and looking at factors needed to give you 711 on the numerator and 100 on the denominator. Then tried to find the combination that work. Would have got it after about an hour of work totaly probably.

[Celeval]

Originally Posted by QuikSand

Trick is to get past the decimals, and think of the prices in pennies 9interegrs are just easier to deal with). With that in mind, the multiplied version has to take the 1/100 exchange into account four times -- meaning that the multiplied value of the four prices is going to be 7.11 expanded by eight decimal places, or rather 711,000,000.

I started here, but didn't expand out the extra decimal places and got lost. Hence moving to brute force.

[Bee]

Originally Posted by rowech

Interesting read....I took the approach of chaning 7.11 to an improper fraction and looking at factors needed to give you 711 on the numerator and 100 on the denominator. Then tried to find the combination that work. Would have got it after about an hour of work totaly probably.

Interesting...my approach was to go to the local 7-11 and have the clerk keep ringing 4 items up until I got to $7.11. The multiplication thing got me though.

[DanGarion]

Depending on what you consider porn there are various 7-11s in SoCal sell Playboy and the illustrious Playboy News Stand Specials (god I loved those when I was younger).

[QuikSand]

I'm pretty sure that the official Southland Corp. policy is no nudies at all - no Playboy, no Black Tail, no nuthin'. I once saw the latter at a 7-Eleven on the Eastern Shore of Maryland (odd in itself) but I guess those are rogue local franchisees.

[rkmsuf]

Originally Posted by QuikSand

I'm pretty sure that the official Southland Corp. policy is no nudies at all - no Playboy, no Black Tail, no nuthin'. I once saw the latter at a 7-Eleven on the Eastern Shore of Maryland (odd in itself) but I guess those are rogue local franchisees.

If someday I could see Quik walking out of a store with the latest Black Tail life would be complete.

[cuervo72]

Originally Posted by QuikSand

I'm pretty sure that the official Southland Corp. policy is no nudies at all - no Playboy, no Black Tail, no nuthin'. I once saw the latter at a 7-Eleven on the Eastern Shore of Maryland (odd in itself) but I guess those are rogue local franchisees.

Dating back into the mid-80's (hi Ed Meese!), probably just a little before the 12/86 "Women of 7-Eleven" pictorial.

[QuikSand]

Good old days... some gold in this thread.