Final answer:
91 out of 100 students voted for green, which means 91% of the students at Ken's school voted for green as the new school color.
Step-by-step explanation:
To find the percentage of students who voted for green, you calculate the ratio of the number of students who voted for green to the total number of students, then multiply by 100 to convert it to a percentage. If 91 students voted for green out of 100 total students, the calculation is as follows:
Percentage of students who voted for green = (Number of students who voted for green / Total number of students) × 100
Percentage of students who voted for green = (91 / 100) × 100 = 91%.
Thus, 91% of the students at Ken's school voted for green as the new school color.