Fraction of students enrolled in Chinese = 
Fraction of students enrolled in French = 
Fraction of students enrolled in Spanish =
Solution:
Total number of students = 51 + 33 + 42
= 126
Number of students enrolled in Chinese = 51
Fraction of students enrolled in Chinese

Fraction of students enrolled in Chinese = 
Number of students enrolled in French = 33
Fraction of students enrolled in French

Fraction of students enrolled in French = 
Number of students enrolled in Spanish = 42
Fraction of students enrolled in Spanish

Fraction of students enrolled in Spanish =
1: -4
2: -2 3/4
3: 1/10
4: 2 1/5

we needed to eliminate w, do so by diving both sides by w and obtain the above result :)
Hope this helps.
The two 3s have different place values. The 3 on the left is in thousands place while the 3 on the right is in the ones place. we can also look at this vc by separating each digit ( 3000 + 400 + 50 + 3)
while the digits are the same, their place determines the value