Bro the answer is 2. Because I’m a high school student. you can trust me
Answer:
12/30
Step-by-step explanation:
So we know that the denominator-numerator=18
And we also know that it's equal to 4/10 or 2/5.
Soooooooooooooo the most easiest is just to trial and error: 12/30
But I don't really know the more complex formula...
You can find additive inverse to find integers and their opposites closed under addition.
This year
2:7
18:?
well 2*9=18
so 7*9=63
18/63
(18+63=total 81 students)
Last year
1/8
multiply by 9
9/72
9 less students this year