How do you get the second number?

Suppose natural gas experiences a 1.9% increase per year in real terms over the foreseeable future. The cost of a 1,000 cubic feet of natural gas is now $7.50. What will be the cost in real terms of 1,000 cubic feet of natural gas in 20 years? If the general price inflation rate (e.g., the CPI) for the next 20 years is expected to average 3.2% per year, what will a 1,000 cubic feet of natural gas cost in actual dollars 20 years from now? The cost of 1,000 cubic feet will be $ The cost of 1,000 cubic feet will be $