Answer :
If the energy generated by the natural gas is 1150 BTUs for each cubic foot of gas, we can find the amount of energy in a tank with 59.4 cubic feet of gas by multiplying this volume by the amount of heat generated per cubic foot:
[tex]Energy=1150\frac{\text{ BTU}}{ft^3}\cdot59.4\text{ }ft^3=1150\cdot59.4\text{ BTU}=68310\text{ BTUs}[/tex]Therefore the amount of energy that can be produced is 68,310 BTUs.