Can I Borrow?Math brain teasers require computations to solve.
This is a teaser for people who know the US coins. My apologies to any out-of-country visitors.
You and a friend pass by a standard coin-operated vending machine and you decide to get a candy bar. The price is US$0.95, but after checking your pockets, you only have a dollar (US$1), and the machine only takes coins.
You turn to your friend and have this conversation.
You: Hey, do you have change for a dollar?
Friend: Let's see... I have 6 US coins but, although they add up to US$1.15, I can't break a dollar.
You: Huh? Can you make change for half a dollar?
You: How about a quarter?
Friend: Nope. And before you ask I can't make change for a dime or nickel either.
You: Really? And these 6 coins are all US government coins currently in production?
You: Well, can you just put your coins into the vending machine and buy me the candy bar, and I'll pay you back?
Friend: Sorry, I'd like to, but I can't with the coins I have.
What coins does your friend have?
HintAs the Jeopardy theme song plays and time is passing...
AnswerYour friend has 4 dimes, a quarter, and a 50 cent piece. They all add up to US$1.15 and he doesn't have change for a dollar, US$0.50, US$0.25, US$0.10, or US$0.05. Also, and here's the trick, he can't buy the candy bar for US$0.95 because a typical US vending machine doesn't take 50 cent coins -- only quarters and below.
See another brain teaser just like this one...
Or, just get a random brain teaser
If you become a registered user you can vote on this brain teaser, keep track of
which ones you have seen, and even make your own.
Back to Top