Given: A person is standing on the first step from the bottom of the ladder. The person climbs 4 more steps to reach the middle step of the ladder.

Let the total number of steps in the ladder be N.

The person is on Step 1. He climbs 4 more steps to reach the middle step. Formula for the middle step: Middle Step = $1 + 4$ $= 5$

Total steps in the ladder: $N = (2 \times 5) - 1$ $= 9$