A landowner wanted to determine the change in the water levels of his pond over time. First, he filled the pond to a water level of five feet. After two weeks, the water level was at 3.4 feet.

Question

If the water level continues to change at that same rate, which of the following statements applies?
A.
For each week that passes, the water level decreases by 1.6 feet.
B.
For each week that passes, the water level decreases by 0.8 foot.
C.
For each week that passes, the water level increases by 1.6 feet.
D.
For each week that passes, the water level increases by 0.8 foot.

Answer 1

To determine the rate of change in the water level of the pond, we can calculate the change in water level over the two-week period.

Initially, the water level was 5 feet, and after two weeks, it was 3.4 feet.

The change in water level is: \[ 5 \text{ feet} - 3.4 \text{ feet} = 1.6 \text{ feet} \]

Since the water level decreased over the two-week period, we can find the rate of change per week by dividing the total change by the number of weeks:

\[ \text{Rate of change per week} = \frac{1.6 \text{ feet}}{2 \text{ weeks}} = 0.8 \text{ feet/week} \]

Since the water level is decreasing, we will express this decrease as a negative change:

\[ \text{Water level decreases by } 0.8 \text{ feet per week.} \]

Therefore, the correct answer is:

B. For each week that passes, the water level decreases by 0.8 foot.