If in a pond there are 20 lotus last year and through reproduction 8 new plants are added, taking current population to 28. The birth rate per year is -

Options

A. 0.4
B. 0.8
C. 2.8
D. 0.28

Answer

To find the birth rate per year of the lotus plants in the pond, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Initial Population**:
- Last year, the number of lotus plants in the pond was 20.

2. **Identify the New Plants Added**:
- This year, through reproduction, 8 new lotus plants were added.

3. **Calculate the Current Population**:
- The current population of lotus plants is 20 (initial) + 8 (new) = 28.

4. **Determine the Birth Rate Formula**:
- The birth rate can be calculated using the formula:
\[ \text{Birth Rate} = \frac{\text{Number of New Individuals}}{\text{Initial Population}} \]

5. **Substitute the Values into the Formula**:
- Here, the number of new individuals is 8, and the initial population is 20.
- Therefore,
\[ \text{Birth Rate} = \frac{8}{20} \]

6. **Calculate the Birth Rate**:
- Simplifying the fraction:
\[ \text{Birth Rate} = 0.4 \]

7. **Conclusion**:
- The birth rate per year for the lotus plants is 0.4.

### Final Answer:
The birth rate per year is **0.4**.

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