The ratio of that question is 7:12
        
             
        
        
        
Answer:
y = 0.75x + 1
Step-by-step explanation:
Here, we want to write an equation in slope-intercept form to represent this information 
Since $1 is the cost of 1 only, this represents our y intercept
It means if we are not interested in purchasing more than 1, our cost will be $1
Now, for each one bought after, we have a rate of $0.75 per one 
Mathematically, that will be $0.75 times the number bought after 
Hence. we have that;
y = 0.75x + 1 
if 1, x = 0; so we have cost of 1 as $1 
 
        
             
        
        
        
1.
If no changes are made, the school has a revenue of :
625*400$/student=250,000$
2.
Assume that the school decides to reduce n*20$.
This means that there will be an increase of 50n students.
Thus there are 625 + 50n students, each paying 400-20n dollars.
The revenue is: 
(625 + 50n)*(400-20n)=12.5(50+n)*20(20-n)=250(n+50)(20-n)
3.
check the options that we have, 
a fee of $380 means that n=1, thus 
250(n+50)(20-n)=250(1+50)(20-1)=242,250   ($)
a fee of $320 means that n=4, thus
 250(n+50)(20-n)=250(4+50)(20-4)=216,000    ($)
the other options cannot be considered since neither 400-275, nor 400-325 are multiples of 20.
Conclusion, neither of the possible choices should be applied, since they will reduce the revenue.
        
             
        
        
        
Answer:
D
Step-by-step explanation:
To find the rate of increase all you have to do is take one of the data sets to see that every two months its charge time increases by 15 minutes or 7.5 minutes every month.
 
        
             
        
        
        
Since the line is parallel, the same coefficients can be used for x and y. The constant on the right needs to change so that the given point will satisfy the equation.
... 5x - 4y = 5(-8) -4(2) = -40 -8 = -48
Your equation is
... 5x -4y = -48