6.3. Three horses participated in the race. A betting office accepts bets with the following odds: for the first horse to win $4: 1$ (i.e., if the first horse wins, the player gets back the money they bet on it and four times as much; otherwise, the player loses all the money they bet), for the second horse $-3: 1$, for the third horse - 1 : 1. Each bet is expressed as a positive integer number of gold coins. Pinocchio has exactly 20 coins. Can he place such bets that he will leave with at least 21 coins regardless of the race outcome?
Solution. To succeed, Pinocchio can act as follows: leave one coin for himself, and from the remaining 19 coins, place 4 coins on the first horse, 5 coins on the second horse, and 10 coins on the third horse. In the event of success for each horse (taking into account the coefficient), he will receive 20 coins, and together with the one coin that Pinocchio did not bet, this will make it possible for him to win.

Answer. Yes.