Bob leaves home with $50.

His birthday approaching, he goes to the neighbourhood bakery to order a birthday cake and pays \$29.95 for the cake, plus \$3.08 for the candles.

Then, he meets three friends in town and they all go grab something to eat: Bob takes a \$4.50 sandwich and a \$0.70 soda.

After that, they all go to the movie theater. Tickets cost \$10, but they can benefit from both an "under 25yo" \$2 discount for each one and a "Free ticket for every three tickets bought" offer, and split the bill equally between them.

They finish the afternoon at a bar, where Bob has two \$2.75 beers while chatting with his friends.

How old is Bob?

  • $\begingroup$ Is he in the USA? $\endgroup$
    – A E
    Nov 12, 2014 at 20:16
  • 1
    $\begingroup$ This seems to lead to an unprovable assumption that he is <25, but they split the bill, so could potentially be a combination of ages. Are we able to assume his friends are the same age as him? $\endgroup$
    – Jon Story
    Nov 13, 2014 at 0:15
  • 1
    $\begingroup$ wait... 75 cent beers? who cares how old he is $\endgroup$ Nov 13, 2014 at 16:11
  • 1
    $\begingroup$ What does Bob do with the remaining 27 cents? $\endgroup$
    – Michael
    Nov 13, 2014 at 17:10
  • 2
    $\begingroup$ @Michael He may shoot someone: link $\endgroup$
    – OxTaz
    Nov 13, 2014 at 17:20

2 Answers 2


Bob is 21. He is under 25 (discount), older than 20 (beer), and the 3.08 for candles works out to 0.14 for each candle for his upcoming birthday (22)

  • $\begingroup$ Almost correct. Which means wrong :) $\endgroup$
    – OxTaz
    Nov 12, 2014 at 20:17
  • $\begingroup$ Yeah yeah, I remembered a factor I forgot. $\endgroup$
    – JonTheMon
    Nov 12, 2014 at 20:18
  • $\begingroup$ And that's correct! I can't believe how fast that was... $\endgroup$
    – OxTaz
    Nov 12, 2014 at 20:19
  • $\begingroup$ @OxTaz don't forget to accept this answer. $\endgroup$
    – warspyking
    Nov 12, 2014 at 20:26
  • 5
    $\begingroup$ Who buys candles individually? I get that is the point of the question but I only see them sold in packs. And where can I get $.75 beers in the USA? $\endgroup$
    – kaine
    Nov 12, 2014 at 21:50

He is celebrating his 22nd birthday.

He has to be at least 18 or 21 (depending on where he is) to buy the beers and less than 25 to get the discount. Dividing the candles by 22 gives a price of 14 cents per candle.

  • $\begingroup$ Actually, while making the puzzle I discovered that in some countries you can drink/purchase alcohol at 16, and had to consider that. $\endgroup$
    – OxTaz
    Nov 13, 2014 at 17:14

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