Answer:
The reason that it takes longer to get the water to boiling temperature than it is to cool it down again is because heating in the most simple sense is inefficient and will cause a lot if energy lost while cooling is to be turn's into quite a efficient process.
Explanation:
A. The cliff was 30.7 m high
B. I also got 9.5 as the horizontal distance
Here is my work, I find making charts like this one to find knowns and unknowns can be helpful