Bat and Ball

Let the ball cost $x$; then the bat costs $x+1$.

Solve $2x+1=1.10$.

1. 1. Equation

   $$x+(x+1)=1.10$$

2. 2. Solve

   $$x=0.05$$

3. 3. Key idea

   Write the equation instead of trusting the intuitive answer of $0.10.

Answer: 0.05