We know that Harmie's average 5-day natural gas usage rate is 5.9 therms/5 days.
We have to calculate the 1 day average usage rate and 8 day average usage rate.
We can calculate this by transforming the denominator from 5 days, as it is in the information given, to 1 day and 8 days respectively:
[tex]\frac{5.9\text{ therms}}{5\text{ days}}\cdot\frac{1\text{ day}}{1\text{ day}}=\frac{5.9}{5}\cdot\frac{\text{therms}}{1\text{ day}}=\frac{1.18\text{ therms}}{1\text{ day}}[/tex][tex]\frac{5.9\text{ therms}}{5\text{ days}}\cdot\frac{8\text{ days}}{8\text{ days}}=(\frac{5.9\cdot8}{5})\cdot\frac{\text{therms}}{8\text{ days}}=\frac{9.44\text{ therms}}{8\text{ days}}[/tex]
Answer: 1.18 therms / 1 day, 9.44 therms / 8 days [Option 1]
