How do I solve this physics problems involving acceleration?

How can I solve this problem or atleast what are the steps I need to take?

Heres the problem:

Our hero, Noah Vale, is out for his afternoon constitutional when he spots the sultry Miss Terius standing at the bottom of a 1225m high cliff. At the top of the cliff is the arch villain, Rotcod Dam, who has dropped a boulder to strike the lovely young miss.
Noah, who is standing still 307.5m away from the cliff when the boulder starts downward, rushes to her resue. Noah, great athlete that he is, can accelerate at 10.00m/s/s, which he does until he reached his maximum velocity of 25.00 m/s. .He then races at the maximum velocity until he must stop to resue her. (Noah, being a truly great athlete can slow as fast as he can speed up, in other words his accceleration while slowing is -10.00m/s/s
Will Noah arrive in time to save our heroine, or will Miss Terius become another victim of physics?
The boulder accelerates at 9.800 m/s/s
You need to know that to solve the problem.