In a certain country, it takes a minimum of exactly 5 coins to make 13 cents, and a minimum of exactly 4 coins to make 14 cents.

What are the denominations of the coins (of value less than 15 cents) in this country?

Bonus: What country is it?

The official solution 2, and 5 cent coins is interesting but unrealistic.  It would never allow you to have 1 cent or 3 cents (every other value is possible.)

There is nothing in the problem that disallows non-integer value coins so I propose the simple coin values of 1, 5 and 3.75
13 = 1+1+1+5+5
14 = 3.75+3.75+3.75+3.75

Now you can make any integer value of cents.

Taking another hint from the official solution:  my country is Jeristan.  The 3.75 cent coins were minted as gifts to commemorate the crown prince turning 45 months old.

Posted by Jer on 2016-03-24 13:38:53