Answer:
76 balls and 24 bats
Explanation:
Set up a system of equations where x is the number of balls and y is the number of bats:
x + y = 100
4.5x + 20y = 822
Solve by elimination by multiplying the top equation by -20, then combine the equations together:
-20x - 20y = -2000
4.5x + 20y = 822
-15.5x = -1178
x = 76
Then, plug in 76 as x in the first equation to solve for y:
x + y = 100
76 + y = 100
y = 24
So, 76 balls and 24 bats were purchased.