Answer:
9
Explanation:
Let's say the starting "middle rung" is equal to 0.
First, he climbs up, so we add 3 and he is now at '3'.
Then, he goes down 5, putting him at '-2'.
And then he goes up 10, which puts him at the highest point, which is '8'.
If we add all of the values together, we get the number of ladders, which is 9.
Forgive me if this is the wrong answer, this is just what I got :)