If 2/5 of the students in the class are girls, what fraction are the boys?
[] Let's say the whole class is equal to 5/5.
[] If there are only girls and boys in the class, then we can do the math 5/5 - 2/5 = 3/5 to find 3/5 of the class is boys
-> 3/5 of the class is boys
If the class has 35 students, how many boys are in the class?
[] With the second part of this problem, we are given more information.
[] Our whole, 5/5 before, is equal to 35. We can multiply 3/5 (boys in the class) by our whole, 35, for our answer.
[] This gives us 21 boys in the class. We can test this by seeing that 3/5 = 21/35, so this solution makes sense.
-> There are 21 boys in the class
Have a nice day!
I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)
- Heather