In order to complete the racing competition, the London racetrack has to submit its top and the most famous three horses to win the competition. Due to a electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the London racetrack. But there can be only five horses at a time on the track. Due to the electrical storm, time recording is impossible. What will the least number of races that can be conducted to find out the three fastest horses?
Find amounts of money that can be made up in two ways so that one set of coins has twice as many coins as the other (but not using only 1c and 2c coins). e.g. 71c is 50c, 20c, 1c (3 coins) or 20c, 20c, 20c, 5c, 5c, 1c (6 coins)
