The problem involves determining the number of cars owned by S based on three statements, given that only one statement is true.
Let $n$ represent the number of cars S owns.
The statements can be represented mathematically:
We are told exactly one of these statements is true.
We test different values for $n$ to see when exactly one statement holds true:
The only scenario where exactly one person (Q) tells the truth is when $n=0$. Therefore, S has 0 cars.
Consider a linear arrangement of seven bulbs, each of which can be in the ON or OFF states. The initial configuration of the bulbs is shown in the figure. In every Step, the states of the bulbs are changed based on the following rules:
The state of bulbs at the end of Step 1 and Step 2 are also shown in the figure.
The number of bulbs which are ON at the end of Step 8 is ______

Consider a five-digit number PQRST that has distinct digits P, Q, R, S and T, and satisfies the following conditions:
$P < Q$
$S > P > T$
$R < T$
If integers 1 through 5 are used to construct such a number, the value of P is: