Answer: 1 large door.
Explanation:
You know that the lenght of each door for the small cabinets is:
Since the lenght of the doors for the large cabinets are 3.9 times as long as the doors for the small candidates, the lenght of any of these doors is:
The lenght of the board is 11 feet, so you need to convert it to inches:
Then, the number of large doors that can be cut from that board is:
So, 1 large door can be cut from that board.