Four friends A, B, C, D, contribute money to a pool. A contributes double the amount C contributes and B contributes half the amount A contributes. D contributes half the amount of B. Which two are contributing equal amount?

Options

A. B,D
B. A,D
C. A,B
D. B,C

Explanation

To solve the problem step by step, let's define the contributions of each friend based on the information given:

1. **Define the contributions**:
- Let the amount contributed by C be \( x \).
- Since A contributes double the amount C contributes, we have:
\[ A = 2x \]
- B contributes half the amount A contributes, so:
\[ B = \frac{1}{2} \times A = \frac{1}{2} \times 2x = x \]
- D contributes half the amount B contributes, thus:
\[ D = \frac{1}{2} \times B = \frac{1}{2} \times x = \frac{x}{2} \]

2. **Summarize the contributions**:
- A contributes \( 2x \)
- B contributes \( x \)
- C contributes \( x \)
- D contributes \( \frac{x}{2} \)

3. **Compare the contributions**:
- From the contributions, we can see:
- A: \( 2x \)
- B: \( x \)
- C: \( x \)
- D: \( \frac{x}{2} \)

4. **Identify equal contributions**:
- B and C both contribute \( x \).
- Therefore, B and C are the two friends contributing equal amounts.

5. **Conclusion**:
- The two friends contributing equal amounts are **B and C**.