When Will the Thrown Mass Overtake the Dropped Shot Put in Freefall?

[yakiland]

Heres a question I am really stuck on...

Homework Statement

If Person A drops a shot put weighing 1.5 kg from a height of 60m, and at exactly the same time Person B throws down a 100g mass at a speed of 10 m/s from 70m up, at what time would the mass overtake the shot put?

Homework Equations

mass is irrelevant due to freefall.

to find the total time it takes for each item to reach the ground, i used
x=(v+u/2)*t
AND
v^2=u^2+2ax

acceleration due to gravity=9.8m/s^2

The Attempt at a Solution

I have no idea where to start...

 

[awvvu]

If you write out the x equations for both the A ball and B ball, then you can equate the two and find the time they occupy the same position.