Okay, add this up; you got 30 girls and 40 boys, that's 70 total students. It says 60% of the girls, so 60% of 30 is 18, and 25% of the guys, so 25% of 40 is 10. So you got 18 girls and 10 boys going, you have 28 students going. 28 is what % of 70? 70 goes into 28 .4 times; therefore, C, 40% of the students went