It is 70% Because:
250/100 + 175/x
Proportions
Step-by-step explanation:
In order to get the inverse of equation, we will interchange the variables and solve for x and y as follows.

whereas, 
or x = 
Now, on interchanging the variable we will get the equation as follows.


y = 
So that is what we call a ratio and it looks like this
It can help them by concentrating like mind games and teaching them. Learning from their mistakes something like that. Like reading games that help you with your subjects.