What was the 1947 value of 7,200 Reichsmarks in U.S. dollars? What was the 1947 exchange rate of the U.S. dollar for the Reichsmark?
That is not really easy to answer, as the German economy was not really in orderly fashion functioning. The black market dominated many sectors of civilian life, internationla trade was "low" and most of the consumer goods were hidden away or distributed via food stamps.
Compare that to Reichsmark:
After the Second World War, the Reichsmark continued to circulate in Germany, but with new banknotes (Allied Occupation Marks) printed in the US and in the Soviet Zone, as well as with coins (without swastikas). In practice, massive inflation dating back to the latter stages of the war had rendered the Reichsmark nearly worthless. For all intents and purposes, it was supplanted by a barter economy (commonly, "cigarette currency").
One online source concludes, that any meaningful exchange rate is therefor not available for 1947:
1941 – RM 2.50
1942-1949 – not available
1950 – DM 4.20
However, using an equivalent of the Big-Mac-Index you might arrive at a somewhat reasonable comparison:
Historical currency converter
Question: What is the equivalent of 7200 German reichsmark [1924-1948] in year 1947 in the currency of US dollar [1791-2015] in year 1947?
7200 German reichsmark [1924-1948] in year 1947 could buy the same amount of consumer goods and services in Sweden as 50.88241517640041 US dollar [1791-2015] could buy in Sweden in year 1947. This comparison should be used if the purpose of the analysis is to compare absolute worth over time rather than relative worth.
Another way to compare the worth of money in different periods is to estimate how much labour power an amount of money could buy. 7200 German reichsmark [1924-1948] in year 1947 was the amount a male worker in Sweden received in wage for 78.3772792951862 hours work. A male worker in Sweden in 1947 received 50.88241517640041 US dollar [1791-2015] in wage for 78.3772792951862 hours worked. This comparison should be used if the purpose of the analysis is to compare relative worth over time rather than absolute worth.
7200 German reichsmark [1924-1948] in year 1947 could buy 45.99775121279953 gram gold. The price of 45.99775121279953 gram gold in year 1947 was 50.88241517640041 US dollar [1791-2015].
7200 German reichsmark [1924-1948] in year 1947 could buy 2241.470416599721 gram silver. The price of 2241.470416599721 gram silver in year 1947 was 50.88241517640041 US dollar [1791-2015].
According to helpful commentator @Snow, this would then be:
Spinning this around gives roughly 141.5 RM for the Dollar in 1947.
If another somewhat theoretical conversion rate is still desired, then Exchange Rates Between the United States Dollar and Forty-one Currencies gives an attempt at:
What Was the Exchange Rate between the U.S. Dollar and Reichsmark?
Germany, 1947 - 1947
1947: 269.1790 Reichsmark