Write the following sets in roster form and also in set builder form :
A = {even whole numbers which are less than 50}

Answer

To solve the problem of writing the set of even whole numbers less than 50 in both roster form and set builder form, we can follow these steps:

### Step 1: Identify the even whole numbers less than 50
Even whole numbers are numbers that can be divided by 2 without a remainder. The even whole numbers less than 50 start from 0 and go up to 48.

### Step 2: List the even whole numbers in roster form
The even whole numbers less than 50 are:
- 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48

So, in roster form, we can write the set as:
\[ A = \{ 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48 \} \]

### Step 3: Write the set in set builder form
In set builder form, we describe the set by stating the properties that its members must satisfy. For this set, we can express it as:
\[ A = \{ x \mid x \text{ is an even whole number and } x < 50 \} \]

### Final Answer
- **Roster Form**:
\[ A = \{ 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48 \} \]

- **Set Builder Form**:
\[ A = \{ x \mid x \text{ is an even whole number and } x < 50 \} \]