I thought that was surprisingly easy, just use (sin30)*60*4, but I ended up with 207.84m, but the answer book said it was 212m? What did I do wrong?

I figured out the vertical component of the initial speed to be 28 m/s, but how can you get the horizontal? I think you may be able to get the horizontal distance with the speed of sound?

You're looking for the horizontal component of distance.

edit: unless there is more given information, your answer is correct. I think you accidentally wrote sin instead of cos.

To solve this one you'll need to realize that the total time (3 sec) is the time it takes for the rock to fall, hit the water, then let the soundwave travel back up to you. Don't worry about horizontal and vertical components, treat it as if he dropped the rock.