Question 1030958
A.  Medicine, which is not taxed  SALES --------X
B.  Non-medical items, which are taxed at the rate of 8%--------------Y
C.  Beer and cigarettes, which are taxed at the "sin tax" rate of 20%---------Z

Last Friday, the total sales (excluding taxes) of all three items were $18,500.

X+Y+Z=18500...............(1)

  The tax collected was $1,020. 

8%Y+20%Z=1020.....................(2)
MULTIPLY BY 100
8Y+20Z=102000
 The sales of medicines exceeded the combined sales of the other items by $3500. 

 X-3500 = y+z......................(3)

 X+(Y+Z)= 18500
X+(X-3500)=18500
2X = 18500+3500

2X= 22000

X= 11,000

Now
8Y +20Z=102000..............4
y+z=7500
8y+8z= 60000.................5

(4-5)

12z=42000
z=3500

y+z=7500
z=3500
y= 4000

Medicine --------------$11,000
B.  Non medical -------$4000
C.  Beer and cigarettes, $3,500