A rocket, initially at rest on the ground, accelerates straight upward from rest with constant acceleration 29.4ms^-2. The acceleration period lasts for time 6.00s until the fuel is exhausted. After that, the rocket is in free fall. Find the maximum height reached by the rocket. Ignore air resistance and assume a constant acceleration due to gravity equal to 9.8ms^-2.

A very simple question, but I can't seem to get the answer. Any help would be greatly appreciated

I know you've to add 2 values for the maximum height. Can't seem to get the correct numerical answer though.