Total of 18 items must be cleared to make the space in the warehouse.
Step-by-step explanation:
Assuming that we are at Point Zero and has removed none of the boxes so far. We would keep a tab on our movement following the cartesian coordinates and increase the box count as we displace any of them.
Step 1- Moving forward 6 feet and removing half a dozen boxed. Hence the box count =6
Step 2- Moving another 9 feet. Clear all 10 crates of the ball bearing. Hence the box count= 16
Step 3-Moving the remaining 15 feet and reach 3 barrels along the far side wall and remove 2 of them. Hence the box count= 18
Step 4-Turn around and come straight back.
Hence the total no of box removed= total box count= 18