What was the dollar value of a Russian rouble in 1931?

In 1931, the value of the Russian rouble was quite unstable due to the economic turmoil following the Russian Revolution and the subsequent civil war. At that time, the official exchange rate was approximately 1 rouble to 0.25 US dollars, but this value fluctuated significantly due to hyperinflation and other economic factors. It's important to note that the rouble had different values in various contexts, including official rates and black market rates.