While mining, nancy found a large metal bar that contain 12 grams of copper. nancy also determined that the bar was 80% copper. what was the total weight of the metal bar in grams?

560

hope this : )

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

3x + 4y -25 =0 represents the amount of change sianna should recieve