Someone is eating a 50 gram chocolate bar which contains 30% cocoa how many grams of cocoa is in the chocolate bar

It's would be 15 grams. Your ratio is x/50=30/100. You then would cross multiply 30×50 and end up with 1500. After that you would divide by 100 and have your answer, 15g.

Well , 10% is 5 g so if you times those 5 g by 3 it is 15 g there are 15 grams of cocoa in the chocolate bar

6/9 i need more characters in my answer