Zero. John can have the store deliver the water. (Lol)

Ceiling[13/3] = Ceiling[4 1/3] = 5 (The ceiling function returns the smallest integer greater than or equal to its argument.)

John would need to make 5 trips to the store.

Ceiling[13/3] = Ceiling[4 1/3] = 5 (The ceiling function returns the smallest integer greater than or equal to its argument.)

John would need to make 5 trips to the store.