Question 179173
if he uses 3 cans per day and he has 27 cans
:
27/3 should give us the amount of days it will last
:
9 days
:
27 cans/ 3 (cans/day)  thats cans/(cans/day)..invert (cans/day) and multiply
:
27/3=9 {{{cross((cans))*(day/cross(cans))=(days)}}} most of the time when you just look at the units you can figure a problem out