Directions (75-79): Read the given number series carefully to answer the related questions:

692    318    196     486 7   54

If we remove even digits from each number in the series than how many prime numbers formed?

The correct option is Two.

Let us analyze the given number series step-by-step. The series is:
692   318   196   486   754
Note: The last two numbers in the series are 486 and 754 (represented with spacing in the question).

To find the number of prime numbers formed, we need to remove all the even digits (2, 4, 6, 8) from each number in the series and check if the remaining number is prime:

1. For the first number, 692:
The digits are 6 (even), 9 (odd), and 2 (even).
Removing the even digits (6 and 2) leaves:
$9$
Since 9 is divisible by 3, it is a composite number (not prime).

2. For the second number, 318:
The digits are 3 (odd), 1 (odd), and 8 (even).
Removing the even digit (8) leaves:
$31$
Since 31 has no factors other than 1 and itself, it is a prime number.

3. For the third number, 196:
The digits are 1 (odd), 9 (odd), and 6 (even).
Removing the even digit (6) leaves:
$19$
Since 19 has no factors other than 1 and itself, it is a prime number.

4. For the fourth number, 486:
All digits (4, 8, 6) are even.
Removing the even digits leaves no digits behind.

5. For the fifth number, 754:
The digits are 7 (odd), 5 (odd), and 4 (even).
Removing the even digit (4) leaves:
$75$
Since 75 is divisible by 3 and 5, it is a composite number (not prime).

Comparing our results, we find that exactly two prime numbers are formed: 31 and 19.