Answer:
the exchange rate between U.S. dollar and German mark be under this system will be of 3 U$D = 1 german mark
Step-by-step explanation:
We will use gold and silver as a mean to equalize both currencies:
First equivalence between silver and gold:
90 francs = 1 ounce of gold
9 franc = 1 ounce of silver
90/9 = 10 ounce of silver equals 1 ounce of gold.
Now, we convert the german mark to gold:
1 german mark = ounce of silver
10 german mark = ounce of gold.
Finally, we equalize with the US dollars:
30 dollar = ounce of gold = 10 german mark
30 dollars = 10 german mark
3 dollars = 1 german mark