Amount- Total

[Guest]

A building is constructed with 3 floors. On each floor the windows consist of several panes of glass.

1st floor- 24 panes of glass in each window.

2nd floor- 20 panes of glass in each window.

3rd floor- 16 panes of glass in each window.

The ratio of the number of windows of the 3 types are 4 : 2 : 1.

The total number of panes lacks 32 of being 9 times the L.C.M. of the sum of the panes in 3 windows, 1 of each type.

Calculate total number of windows.

How do I proceed ?