If you have a spinning wheel with 3-green sectors, 1-blue sector and 1-red sector.

Number of green sectors in the wheel $=3$

Number of blue sectors in the wheel $=1$

Number of red sectors in the wheel $=1$

Total number of sectors in the wheel $=3+1+1=5$

$\therefore$ Number of possible outcomes $=5$

Let $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ be the events of getting a green, blue and red sector, respectively.

$\therefore \mathrm{P}(\mathrm{A})=\frac{3}{5}, \mathrm{P}(\mathrm{B})=\frac{1}{5}$ and $\mathrm{P}(\mathrm{C})=\frac{1}{5}$

Hence, the probability of getting a green sector is the maximum.