Question

49. Assertion: The unit digit of cube of 128, 38 and 48 is 4.

Reason: If a number ends with 8, then its cube ends with 2.

Answer 1

To evaluate the assertion and reason, let's analyze the units digit of the cubes of the numbers given:

1. **128**: The unit digit is **8**.
- The cube of a number that ends in 8 (like 8) is calculated as follows:
\(8^3 = 512\) which ends in **2**.

2. **38**: The unit digit is also **8**.
- Again, \(8^3 = 512\) which ends in **2**.

3. **48**: The unit digit is again **8**.
- Similarly, \(8^3 = 512\) which ends in **2**.

Now, none of these numbers (128, 38, and 48) have cubes that end in **4**; in fact, they all end in **2**.

Thus, the **Assertion** is **false** because the unit digit of the cube of each of these numbers is not 4.

Now, examining the **Reason**: The statement "If a number ends with 8, then its cube ends with 2" is **true**.

Therefore, the final evaluation is:

- The **Assertion** is **false**.
- The **Reason** is **true**.

In conclusion, the answer would be that the assertion is incorrect, but the reasoning is correct.