Math Is Fun Forum

I have this question...

A girl throws a ball vertically upwards with a speed of 8 m/s from a window which is 6 m above the horizontal ground.
a) find the geatist hight reached by the ball.

I managd to do this question with an answer of 9.27m.

This is the question with wich i am struggaling...

1.5 s later she drops a second ball from rest out of the same window.
b) Find the distance below the window at which the balls meet.

Thanks all!
Matt