Step 1: fill up the 13kg jar.
Step 2: 5kg jar should be taken away from the 13kg. (Twice)
Step 3: left in the 13kg jar after step 2 would be 3kg.
Step 4: pour the 3kg on a side on the floor.
Step 5: repeat step 1.
Step 6: repeat step 2.
Step 7: repeat step 4.
On the floor after step 7 would be 6kg of rice.
Step 8: pour the 6kg of rice into the 13kg jar and add a full 5kg jar of rice into the same 13kg jar.
BOOM= YOU HAVE 11KG.