If a school cafeteria needs C cans of soup each week for each student, and if there are S students in the school, for how many weeks will X cans of soup last?

X/SC

X/CX

XS/C

None of these

C for each week
S students
how many weeks will X last?
let the number of weeks be W.
for each week, there will be X/W cans of soup.

Each student will take C cans of soup
So S students will take SC cans
we know X/W = SC
W= X/SC