A tower stands on the top of a building which is 40 metres high. The angles of depression of a point situated on the ground from the top and the bottom of the tower are found to be 60° and 45° respectively. What is the height (in metres) of the tower?
1
20√3
2
30(√3 + 1)
3
40(√3 - 1)
4
50(√3 - 1)