1. Which one of the following pairs is different from the other four?

2. In the sequence below, how many even numbers are immediately preceded by 6 as well as immediately followed by 3?

Sequence: 6656839436736432864682663

3. How many 3s are there in the following number sequence which are immediately preceded by 6 but not immediately followed by 7? Sequence:

2 3 7 4 3 5 6 3 7 4 6 3 8 9 6 3 5 1 8 3 7 2 4 2 8 6 3 9

4. In a row of 36 pupils, the first boy is followed by one girl, the second boy is followed by two girls, the third boy is followed by three girls, and so on. What is the number of girls in the second half of the row?

5. In a queue of 13 persons buying tickets from a counter, if every second person from the counter is female and the person at the beginning and at the end of the queue is also female, how many persons in the queue are male?

6. Which of the following will be the middle digits of the middle number after reversing the digits of the following numbers:

372, 981, 846, 263, 589?

7. How many numbers from 1 to 100 are there, each of which is not only exactly divisible by 4 but also has 4 as a digit in it?

8. How many numbers from 6 to 66 are divisible by 7?

9. A number is greater than 6 but less than 10. Also, it is greater than 7 but less than 9. Then the number is:

10. How many numbers from 11 to 50 are divisible by 6 but not by 4?