I cannot figure out how to solve this problem
There are 131 students in three classes. The second class has 9 more students than the first and then the third class has 20 more students than the second. how many students does the first class have?
please help
You should always start "word problems" by choosing variables to stand for the numbers mentioned in the problem which you don't know.
I see that the problem talks about the number of students in the first class, the number of students in the second class, and the number of students in the third class. So, it seems reasonable to me to do this:
let f = number of students in the first class
let s = number of students in the second class
let t = number of students in the third class.
Now, the problem states that there are 131 students in the three classes (altogether, we must assume). So,
f + s + t = 131
Then, it says "the second class has 9 more students than the first". We could write that as
s = f + 9
There's another fact in the problem....see if you can translate that fact into a mathematical statement.
You will then have THREE equations with THREE variables; you should have been studying ways to solve a system of equations.
Please show us how far you can take this on your own now, so that we may see where your difficulties lie.
