That is, a group has 3+2+ 1 = 6 (balloons), 50 ÷ 6 = 8 (groups) ... 2 (balloons), and the remaining two are Le Ballon Rouge.
So the red balloon has 3× 8+2 = 26, the yellow balloon has 2× 8 = 16, and the blue balloon has 8.
The number of red balloons accounts for 26 ÷ 50 =13/25 of the total number of balloons;
The number of yellow balloons accounts for16 ÷ 50 = 8/25 of the total balloons;
The number of blue balloons is 8/50 = 4/25 of the total number of balloons.