23 should be reserved because if there are 738 students going on a field trip and each bus can only hold 33 students then they will require many buses (Wow, that's a lot of students...) Ok so first of all to find how many buses we need, we need to divide 738 by 33
738/33 = 22.3636363636
but since students and buses can't be split in half (without causing harm at least) we need to round it, once rounded we are left with 22 buses but where do the rest of the students go? That's why we have to bump 22 up by 1 giving us 23, therefore allowing all the students to come, Thus your only viable solution is 23!
