Answer:
 The cost of the 1 muffin is $1.5 and 1 quart of milk cost is $3 .
Step-by-step explanation:
Let us assume that the cost of one muffins be x.
Let us assume that the cost of one 1 quarts of milk be y.
As given
The cost of 8 muffins and 2 quarts of mil is $18.
Than the equation becomes
8x + 2y = 18 
As given
The cost of 3 muffins and 1 quart of milk is $7.50.
Than the equation becomes
3x + 1y = 7.50 
Two equations are
8x + 2y = 18  and 3x + 1y = 7.50 
Multiply  3x + 1y = 7.50 by 2 and subtracted from 8x + 2y = 18 .
Thus
8x - 6x + 2y - 2y = 18 - 15
 2x  =  3

x = 1.5 
Put x = 1.5 in 3x + 1y = 7.50 
3 × 1.5 + y = 7.50
y = 7.50 - 4.5
y = 3
Therefore the cost of the 1 muffin is $1.5 and 1 quart of milk cost is $3 .
 
        
             
        
        
        
Answer:
40.5
Step-by-step explanation:
This answer makes sense because we know that 50% of 90 is 45. 
Since 45% of 90 is 40.5, we can self-check our answer.
Hope I helped!
~PumpkinSpice1♥
 
        
                    
             
        
        
        
Answer:
Y = 10/7X + 4
Y intercept = 4
Slope = 10/7
X intercept = -40/7
Step-by-step explanation:
Incase you are asked the equation of the line 
The slope intercept equation is as follows -
(1)....Y = mx + b
where m - Slope
 b - Y - intercept
the standard formula of slope which is commonly referred to as "the rate of change" is -
(2) .....m= Y2 - Y1 / X2 - X1
in this case you can refer to the final and initial X and Y values directly from the small points on the line.
and so(3)..... - X1 = -6 X2 = 6 
 - Y2 = 9 Y1 = -1 
the y intercept is defined as the value we get whenever X id zero. and X has a value of zero when a line crosses the y axis. 
thus, X = 0 & Y = 4 ( 0 , 4 )
now lets substitute our values(3) into the slope formula (equation 2) 
m = 9 - - 1 / 6 - - 1 = 10/7 
now that we found the line's slope, let's simply plug the y intercept 
into the slope intercept formula (1)
Y = 10/7X + 4 
 
        
             
        
        
        
Money earned: 8*4 = $32
Tips needed: 100-32 = $68
If he keeps 90%, the total money he needs to earn in tips is (10/9)*68 = $75.55
        
             
        
        
        
86,170 - 79,860 = 6310
You want to find the difference between the two
6310