(btw idk if this is an official way of solving but it works soo..)
first: 3 /0.6 = 5i know how much 0.6m weighs so im going to use that info to my advantage
second: 5 x 3.2 = 16since i know the entire piece of metal is equal to 5 parts that each equal 3.2kg i just multiply the numbers to get the total weight
third: 16 - 3.2 = 12.8since the total weight was not the answer they wanted, and they wanted the weight of the larger piece you simply subtract what the smaller amount weighed from the total and you get the final answer of 12.8kg
i hope this explanation was clear enough..
ahhmm i think none? nahh