We need to find the percentage increase in the temperature of the piece of metal. The percentage increase in any value is given by the relation as follows :
So, the required percentage increase in the temperature of the piece of metal is equal to 12.5%.
I believe the most logical answer would be is to divide so us the kcf method keep change flip so 5 stays the same then change division into multiplication then flip the fraction 1/3 into 3/1 so now we have 5 times 3 is 15