3) At a skating rink, the people skating produced 64,800 BTUs (British Thermal Units) of heat. The interior of the skating rink is 90 feet long, 40 feet wide, and 20 feet tall. To the
nearest thousandth, how many BTUs per cubic foot did they produce?
a) 0.90 BTUs/fl 3
b) 0.03 BTUs/ft 3
c) 0.67 BTUs/ft 3
d) 1.11 BTUs/ft 3