Answer:
What you first want to do is see what all of the numver of students add up to:
80 + 40 = 120
120 + 24 = 144
144 + 56 = 200
So there are a total of 200 votes. 40 of the 200 vote mystery, so you need to find how many times 40 will go into 200. To find this you can just divide.
200/40 = 5
5% prefer mystery books!
Explanation:
Hope it helps! =D
I think I did the math wrong, but just by looking Im pretty sure its 5%