Read the following statements and select the option which is NOT true based on the statements :
The cost of six mangoes is equal to the cost of four apples. The cost of eight apples is equal to the cost of two jackfruits.

Options

A. A mango is not as costly as an apple.
B. An apple is cheaper than a jackfruit.
C. Jackfruit is the costliest of all
D. An apple is not as costly as mango.

Answer

To solve the question, we need to analyze the statements given and determine which option is NOT true based on the relationships between the costs of mangoes, apples, and jackfruits.

### Step-by-Step Solution:

1. **Understanding the Relationships**:
- The cost of 6 mangoes is equal to the cost of 4 apples.
- The cost of 8 apples is equal to the cost of 2 jackfruits.

2. **Setting Up the Equations**:
- Let the cost of one mango be \( M \), the cost of one apple be \( A \), and the cost of one jackfruit be \( J \).
- From the first statement:
\[ 6M = 4A \quad \Rightarrow \quad M = \frac{4A}{6} = \frac{2A}{3} \]
- From the second statement:
\[ 8A = 2J \quad \Rightarrow \quad J = \frac{8A}{2} = 4A \]

3. **Comparing Costs**:
- Now we have:
- Cost of one mango: \( M = \frac{2A}{3} \)
- Cost of one jackfruit: \( J = 4A \)

4. **Analyzing the Statements**:
- **Statement A**: A mango is not as costly as an apple.
- Since \( M = \frac{2A}{3} \), this is true because \( \frac{2A}{3} < A \).
- **Statement B**: An apple is cheaper than a jackfruit.
- Since \( J = 4A \), this is also true because \( A < 4A \).
- **Statement C**: Jackfruit is the costliest of all.
- This is true as \( J = 4A \) is greater than both \( A \) and \( M \).
- **Statement D**: An apple is not as costly as a mango.
- This is false because \( A > M \) (since \( A > \frac{2A}{3} \)).

5. **Conclusion**:
- The statement that is NOT true is **Statement D**: "An apple is not as costly as a mango."

### Final Answer:
The option which is NOT true based on the statements is **D**.