Answer:
The number of classrooms needed to accommodate all the classes is 22.
Explanation:
[text}N_{classes} / N_{time slots} = N_{classrooms}[/text]
281 / 13 = 21.6; the number of classrooms needed to accommodate all the classes is 22.
To calculate the number of classrooms that you need to accommodate 281 different classes in 13 time slots, you have to divide the number of classes (281) by the number of time slots (13). The result is 21.6 classrooms needed. However, because you cannot have a class to a 0.6 classroom, you have to round up to 22.