The result of RREF produced the following matrix. What is the solution of the system? Choose the best answer.
1 0 3 0
0 1 0 5
0 0 0 1

In a small section of a stadium there are 40 spectators watching a game between the cook islands and fiji. they all support at least one of the two teams. 25 spectators support the cook islands and 16 of these support both teams. how many support only fiji?