Answer:
8 ten dollar bills
20 fifty dollar bills
Explanation:
x = number of 10 dollar bills
y = number of 50 dollar bills
x+y = 28
10x+50y = 1080
Multiply the first equation by -10
-10x -10y = -280
Add this to the second equation
-10x -10y = -280
10x+50y = 1080
-----------------------
40y = 800
Divide by 40
40y/40 = 800/40
y = 20
Now find x
x+y =28
x+20 = 28
x = 28-20
x= 8