Answer
The room can accommodate up to 26 students
Work Step by Step
Dimensions are: 20-foot by 12-foot
Thus area of room = 20(12) = 240 square feet.
Since every student needs a minimum of 9 square feet,
total students that can be accommodate are : $\frac{240}{9}$ = 26.667.
But, students cannot be in fractions, thus the nearest number lower than 26.667 is 26.
Thus the room can accommodate 26 students.