Recall that to determine the percentage of decrease, we can use the following formula:
[tex]PD=\frac{\text{Old value-New Value}}{Old\text{ value}}\times100.[/tex]Substituting the given values in the above formula, we get:
[tex]\frac{2.80-2.73}{2.80}\times100.[/tex]Simplifying the above result, we get:
[tex]0.025\times100=2.5.[/tex]Answer: 2.5%.
