If there are 28 students, we can assume that there are also 28 sticks. There are 4 different colors, with the same number of sticks of each color. So, to find how many sticks of each color there are, we can do 28/4 = 7 sticks.
The probability of the first stick being green would be 7 (since there are 7 green sticks possible to choose from) / 28 (since there are 28 sticks total). This simplifies to:
7/28 = 1/4