Projectile motion question

[Rectophobia]

My physics teacher gave me this question as a challenge when we started projectile motion at the end of last week.

A man is standing at the top of a hill with a constant slope of 20 degrees. He throws a ball at an angle of 30 degrees to the horizontal with an initial velocity of 15ms^-1. Ignoring air resistance, find the time taken to hit the ground (given that   the hill is infinite), how far it travels horizontally and how far down the slope it reaches before it hits the ground?

I did my best to work it out and my answer seems to make sense, but I thought it would be a good idea if I had some input before I check.

Attached are my workings out (ignore the rubik's cube stuff in the top right corner).

[Jaswinder]

Just a question, wouldn't you need to know the mans height and from what distance above the hill he throws the ball from?

[availn]

Just a question, wouldn't you need to know the mans height and from what distance above the hill he throws the ball from?

Yeah, you would, but given the information, I guess you just assume that the ball starts on the ground.

Everything you wrote is correct. You won't be getting this sort of stuff on the exam though