Relative motion problem

How can I solve this problem below.

At t=0, wedge A starts moving to the right with a constant acceleration of 100 mm/s^2 and block B starts moving along the wedge toward the left with a constant acceleration of 150 mm/s^2 relative to the wedge.
Determine the acceleration of block B.

The answer for verification is 80.7 mm/s^2 with an angle of 68.3 degree west of south.