Answer :
Multiply the number of rows with container.
6×12= 72
39 containers have been already set, but there's 72 total.
Subtract the overall number of containers by the containers already set.
72-39=33
6×12= 72
39 containers have been already set, but there's 72 total.
Subtract the overall number of containers by the containers already set.
72-39=33