You can solve this with a system of equations.
B = How much the bat costs
S = How much the ball costs
The bat and the ball together cost 1.10, so your first equation will be b + s = 1.10. You also know that the bat costs 1 dollar more than the ball, so your second equation will be s + 1 = b. Now, since the second equation is already solved for b, plug that value into the first equation.
b + s = 1.10 Plug in the b-value
s + 1 + s = 1.10 Combine like terms (s and s)
2s + 1 = 1.10 Subtreact 1 from both sides
2s = .10 Divide both sides by 2
s = .05
Now, plug the s value into the second equation and solve for b.
s + 1 = b Plug in the s-value
.05 + 1 = b Add
1.05 = b
Now you know that the bat costs $1.05 and the ball costs $.05