120 students are in the 7th grade.
A simple way to tell which type of sentence it is is by Using these tips:
If your sentence has conjunctions such as but, for, nor, or and yet; your sentence is a compound sentence I believe.
And if it has 'more complex' subordinating conjunctions such as although, after, because, when, since, if , unless, while, even though, whenever... your sentence could be complex!
Hope this helped.
2/8= 1/4
2/10=1/5
-Hope this helps.