Well, this is going to be two squared, two squared. Well, this is 2.25 plus four, which is equal to 6.25. So the variance on the round trip is equal to 6.25. If I were to take the square root of that, which is equal to 2.5, we can now describe the normal distribution of the round trip and use that to answer the question. So we have this normal distribution that might look something like this. We know its mean is 20 liters. So this is 20 liters.