Suppose the price per gallon of unleaded gasoline in the southeast region of the United States is normally distributed with a mean of $2.75 and standard deviation of $0.40.

Suppose you take a random sample of 50 gas stations in that area.What is the probability that the average price per gallon is between $2.60 and $2.90?

Choose one:

0.0056

0.0112

0.0040

0.0080

Please explain how to calculate the probability?