Question

This passage describes fur color in rock pocket mice.

a rock pocket mouse with brown fur
A rock pocket mouse may have either brown fur or black fur. These fur colors can help mice hide from predators. For example, a mouse with brown fur can blend in with brown sand.
The table below describes a possible population of rock pocket mice at the start of a period of time and at the end of that period. The table shows fur color in the population at each point in time.
Complete the table. Write the exact answers as whole numbers or decimals.
Data about a population of rock pocket mice
Point in time Number with brown fur Number with black fur Percentage with brown fur Percentage with black fur
Start 77 363
%
%
End 488 312
%
%

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Answer 1

To complete the table with percentages, we need to calculate the total population of rock pocket mice at both the starting and ending points, and then determine the percentage of mice with brown and black fur.

### For the Start:
- **Number with brown fur**: 77
- **Number with black fur**: 363

**Total population at the start**:
\[
\text{Total} = \text{Number with brown fur} + \text{Number with black fur} = 77 + 363 = 440
\]

**Percentage with brown fur**:
\[
\text{Percentage with brown fur} = \left(\frac{\text{Number with brown fur}}{\text{Total population}}\right) \times 100 = \left(\frac{77}{440}\right) \times 100 \approx 17.5\%
\]

**Percentage with black fur**:
\[
\text{Percentage with black fur} = \left(\frac{\text{Number with black fur}}{\text{Total population}}\right) \times 100 = \left(\frac{363}{440}\right) \times 100 \approx 82.5\%
\]

### For the End:
- **Number with brown fur**: 488
- **Number with black fur**: 312

**Total population at the end**:
\[
\text{Total} = \text{Number with brown fur} + \text{Number with black fur} = 488 + 312 = 800
\]

**Percentage with brown fur**:
\[
\text{Percentage with brown fur} = \left(\frac{\text{Number with brown fur}}{\text{Total population}}\right) \times 100 = \left(\frac{488}{800}\right) \times 100 = 61\%
\]

**Percentage with black fur**:
\[
\text{Percentage with black fur} = \left(\frac{\text{Number with black fur}}{\text{Total population}}\right) \times 100 = \left(\frac{312}{800}\right) \times 100 = 39\%
\]

### Final Table:

| Point in time | Number with brown fur | Number with black fur | Percentage with brown fur | Percentage with black fur |
|---------------|-----------------------|-----------------------|---------------------------|--------------------------|
| Start | 77 | 363 | 17.5% | 82.5% |
| End | 488 | 312 | 61% | 39% |

Thus, you can fill in the calculations accordingly.