Finding the heght with bearings

Bob and Shelila are standing on a road 150m apart. A tower is due north of Bob and on a bearing of 070 degrees T from Shelila. The top of the tower appears at an angle of elevation of 27 degrees to Shelila and 18 degrees to Bob.

Find the height of the tower above the road. what assumptions need to be made?

**My attempt- **

assumptions- the location of jack from rosa and the tower.

3 simultaneous equations:

rosa: tan18deg= h/x (i)

jack: tan27deg= h/y (ii)

3rd: 150^2=x^2+y^2 - 2xy cos 70deg (iii)

steps:

1. make h the subject in (i)

2. sub h=__ into (ii)

3. make x or y the subject

4. sub x/y=___ into (iii)

5. solve for x/y

this isnt working for me. (Worried) please help?