Final answer:
In West Berlin, the currency used for financial transactions such as purchasing tickets for P&G was the Deutsche Mark, introduced by Western Allies after World War II to stabilize the economy and facilitate the Marshall Plan.
Step-by-step explanation:
When people were paying for tickets for P&G in West Berlin, they were using the Deutsche Mark. After World War II, the economy of Germany underwent significant struggles, leading to hyperinflation of its earlier currency, the Mark, during the era of the Weimar Republic. This condition rendered the Mark practically worthless.
However, the situation evolved with the Cold War when Western Allies, in an effort to stabilize the economy and dispense Marshall Plan funds, introduced the Deutsche Mark in 1948 in their occupied zones, including West Berlin. This new currency was essential to the economic recovery of West Germany and West Berlin and was in use during the period known as the Berlin Blockade, when the Soviet Union attempted to isolate West Berlin economically.