Question

During the summer months, the water level in Marra’s pool decreases by about 1/2 inch each day due to evaporation. Which equation shows the approximate total change, in inches, to the water level in her pool after 30 summer days?

Answer 1

To find the total change in the water level of Marra's pool after 30 days, we will multiply the daily change (which is a decrease of 1/2 inch) by the number of days (30).

The equation for the total change in water level (in inches) after 30 days can be expressed as:

\[
\text{Total Change} = \text{Daily Change} \times \text{Number of Days}
\]

Substituting in the values we have:

\[
\text{Total Change} = \left(-\frac{1}{2}\right) \times 30
\]

So, the equation that shows the approximate total change, in inches, to the water level in her pool after 30 summer days is:

\[
\text{Total Change} = -\frac{1}{2} \times 30
\]

Calculating this gives:

\[
\text{Total Change} = -15
\]

Thus, the water level in Marra’s pool decreases by approximately 15 inches after 30 days.

Answer 2

During the summer months, the water level in Marra’s pool decreases by about 1/2 inch each day due to evaporation. Which equation shows the approximate total change, in inches, to the water level in her pool after 30 summer days?

A-1/2(-30) =15
B 1/2 (30) =-15
C -1/2(30) = -15
D. 1/2(30) =15

Answer 3

To find the total change in the water level of Marra's pool after 30 days, considering that the water level decreases by \( \frac{1}{2} \) inch each day due to evaporation, we should use a negative sign to indicate a decrease.

The correct equation that represents this total change after 30 days would be:

\[
\text{Total Change} = -\frac{1}{2}(30)
\]

Calculating this yields:

\[
\text{Total Change} = -15
\]

This matches with option **C**:

C. \(-\frac{1}{2}(30) = -15\)

So, the correct answer is **C**.