How many positive integers between 300 and 599, inclusive 1. are divisible by 3? 2. are divisible by 7? 3. are divisible by 3 and by 7? 4. are divisible by 7 but not by 3? Question 2 We want to split a class of 20 students (10 boys, 10 girls) into groups of 4. (use a formula) 1. How many combinations of 4 students are possible? 2. How many combinations contain only boys? Only girls? 3. How many combinations of 4 students are there containing at least one girl? 4. How many combinations are mixed (at least one boy and at least one girl)? 5. How many combinations are balanced? (exactly two boys and two girls)?