This guy doesnt even know what hes talking about. the answer is wrong cause i just took a quiz on it

Asample of rose gold is: 12.0 g gold, 5.0g silver, and 7.0 g copper. what is the percent copper in the sample?

What is the subscript for oxygen in its molecular formula

28. which is not a reason that water is used to store spent fuel rods from nuclear power plants? water increases the speed of the chain reaction in the fuel rods. water protects nuclear power plant workers from the high temperature and radiation of the fuel rods. water acts as a radiation shield to reduce the radiation levels. water cools the spent rods. salts action