Answer:
During the span of 9 days, the water level of lake decreased by 18 inches.
Step-by-step explanation:
We are given the following information in the question:
For 8 hot days, the water level decreased in a lake at rate of 3 inches per day.
Then on day 9, there was a storm that increased the water level by 6 inches.
Total drop in water level in lake =
\(\text{Number of days}\times \text{Rate of drop in water level per day}\\= 8\times 3\text{inches per day}\\=24\text{ inches}\)
Expression for the change in the water level =
\(\text{Increase in water level in 9 days} - \text{Decrease in water level during 9 days}\\=6 - 24\\ = -24 + 6 = -18\text{ inches}\)
Hence, during the span of 9 days, the water level of lake decreased by 18 inches.
