Answer:
Percentage decrease in the reservoir level is 75%.
Step-by-step explanation:
Initial level of the water in the reservoir was recorded = 28 feet
Level of water at the reservoir after the drop = 7 feet
Decrease in the water level = (28 - 7) = 21 feet
Now to calculate the percentage drop we will apply the formula,
Percentage change = [tex]\frac{\text{Net change}}{\text{Initial level}}\times 100[/tex]
= [tex]\frac{21}{28}\times 100[/tex]
= 75%
Percentage decrease in the reservoir level is 75%.