Suppose there are signs on the doors to two rooms. The sign on the first door reads "In this room there is a lady, and in the other one there is a tiger"; and the sign on the second door reads "In one of these rooms, there is a lady, and in one of them there is a tiger." Suppose that you know that one of these signs is true and the other is false. Behind which door is the lady?

The lady is on the second door

Step-by-step explanation:

we have that

The sign on the first door reads "In this room there is a lady, and in the other one there is a tiger"

The sign on the second door reads "In one of these rooms, there is a lady, and in one of them there is a tiger."

so

The sign on the second door is true

The sign on the first door is true or false

Since one of these signs is true and the other is false, the sign in the first door must be false

therefore

The lady is on the second door