Question 277508
Sorry, Charles, but that answer is incorrect. You subtracted 10 from each group, totaling 20. You need to subtract 5 from each group. Either way though, it doesn't matter. This is a mutually exclusive problem. 

I think this is pretty straightforward - 30 take math, 20 take chemistry, and 10 overlap. The question specifically states "....randomly selected student taking math OR chemistry?"

40%.

30(M)+ 20(C)-10(M&C)=40/100