Very simple mathematics:
x = Cost of a ball.
y = Cost of a bat.
This gives us the following two equations:
x + y = $110 (1)
y = x + $100 (2)
Substitute (2) into (1):
x + (x + $100) = $110
So:
2x + $100 = $110
So:
2x = $10
So:
x = $5
x = Cost of a ball.
y = Cost of a bat.
This gives us the following two equations:
x + y = $110 (1)
y = x + $100 (2)
Substitute (2) into (1):
x + (x + $100) = $110
So:
2x + $100 = $110
So:
2x = $10
So:
x = $5