A hoarding is fitted above a building.The height of the building is 12 m.When I look at the lights fitted on the top of the hoarding from a nearby bus stop,the angle of elevation is `50^@` and when i look at the top of the building (terrace) from the same bus stop the angle of elevation is `45^@`.If the height of flat on each floor is equal to the height of the hoarding,the maximum no of floors in the building are: