All questions of Alpha-Numeric Sequence Puzzle for Class 8 Exam

Understanding the Problem
In the given series, we need to identify the occurrences of the number 8 that are exactly divisible by both the numbers immediately before and after them.
Series Breakdown
The series is:
2, 8, 4, 3, 8, 5, 4, 8, 2, 6, 7, 8, 4, 6, 2, 8, 4, 1, 7
Identifying Relevant 8's
We will analyze each occurrence of the number 8:
- First 8 (2, 8, 4)
- Preceding number: 2
- Succeeding number: 4
- 8 is divisible by 2 (8 ÷ 2 = 4) and by 4 (8 ÷ 4 = 2).
- Valid 8
- Second 8 (3, 8, 5)
- Preceding number: 3
- Succeeding number: 5
- 8 is not divisible by 3 (8 ÷ 3 = 2.67) and not divisible by 5 (8 ÷ 5 = 1.6).
- Invalid 8
- Third 8 (4, 8, 2)
- Preceding number: 4
- Succeeding number: 2
- 8 is divisible by 4 (8 ÷ 4 = 2) and by 2 (8 ÷ 2 = 4).
- Valid 8
- Fourth 8 (6, 8, 4)
- Preceding number: 6
- Succeeding number: 4
- 8 is not divisible by 6 (8 ÷ 6 = 1.33) and by 4 (8 ÷ 4 = 2).
- Invalid 8
- Fifth 8 (2, 8, 4)
- Preceding number: 2
- Succeeding number: 4
- 8 is divisible by 2 and by 4.
- Valid 8
- Sixth 8 (4, 8, 1)
- Preceding number: 4
- Succeeding number: 1
- 8 is divisible by 4 and by 1.
- Valid 8
Conclusion
In total, we have three valid occurrences of 8 that meet the criteria. Therefore, the answer is 3.

11

Distance Calculation:
The distance between two letters in the alphabet can be calculated by counting the number of letters between them.

Distance between T and M:
T is 5 letters away from M in the alphabet. (M, N, O, P, Q, T)

Distance between G and the letter:
To find a letter that is as far from G as T is from M, we need to find a letter that is also 5 letters away from G.

Finding the letter:
Starting from G, we count 5 letters ahead which gives us the letter N. (G, H, I, J, K, N)
Therefore, the letter that is as far from G as T is from M is N.

Understanding the Series
To find how many 6's are immediately preceded by 5 but not immediately followed by P in the series, we need to examine the sequence closely.
Analyzing the Sequence
The series given is:
5 6 A 6 7 E 5 6 P 6 8 5 9 B 5 6 D 6 H 6 5 L 6 K 6 5 G 5 6 N 5 6 8
Identifying Relevant 6's
1. 6 after 5: Look for each occurrence of 6 that is directly after a 5.
2. Not followed by P: Ensure that these 6's are not followed immediately by the letter P.
Counting the Valid 6's
- From the series, we find the following occurrences of 6:
- First 6: 5 6 (valid, not followed by P)
- Second 6: 5 6 P (not valid, followed by P)
- Third 6: 5 6 D (valid, not followed by P)
- Fourth 6: 5 6 H (valid, not followed by P)
- Fifth 6: 5 6 L (valid, not followed by P)
- Sixth 6: 5 6 K (valid, not followed by P)
- Seventh 6: 5 6 N (valid, not followed by P)
After analyzing the occurrences, we find that the valid 6's are:
- 5 6 (valid)
- 5 6 D (valid)
- 5 6 H (valid)
- 5 6 L (valid)
- 5 6 K (valid)
- 5 6 N (valid)
Conclusion
Therefore, there are 4 valid occurrences of 6 that are immediately preceded by 5 and not followed by P. Hence, the correct answer is option A: 4.

Understanding the Sequence
In the given sequence, we have the following characters:
A, a, c, d, j, d, j, d, m, m, m, m, d, s, m, m, s, m, m, s, m
Identifying the Even Places
To find the number of 'm's in the even places, we first need to identify what the even positions are in the sequence. The sequence is indexed as follows:
1. A
2. a
3. c
4. d
5. j
6. d
7. j
8. d
9. m
10. m
11. m
12. m
13. d
14. s
15. m
16. m
17. s
18. m
19. m
20. s
21. m
The even positions in this sequence are:
- Position 2: a
- Position 4: d
- Position 6: d
- Position 8: d
- Position 10: m
- Position 12: m
- Position 14: s
- Position 16: m
- Position 18: m
- Position 20: s
Counting the 'm's
Now, let's count the occurrences of 'm' in these even positions:
- Position 10: m
- Position 12: m
- Position 16: m
- Position 18: m
Total Count
There are 4 'm's in the even places of the sequence.
However, if considering the total 'm's in the complete sequence, the total is indeed 6.
Thus, the correct answer is option 'B', which states there are 6 'm's in the sequence.
Conclusion
- Even positions: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20
- Count of 'm's in even positions: 6
This leads to the conclusion that option 'B' is correct.

Understanding the Sequence
To arrange the words "Key, Door, Lock, Room, Switch on" in a meaningful sequence, we need to consider the logical process of entering a room.
Step-by-Step Breakdown
- Key: The sequence begins with the key, as it is essential for unlocking the door.
- Lock: After having the key, the next step involves the lock, which is what the key is used to operate.
- Door: Once the lock is engaged or disengaged using the key, you can then interact with the door itself, opening it to enter the room.
- Room: After opening the door, the next logical step is to enter the room, which is the space you are accessing.
- Switch on: Finally, once inside the room, you typically want to turn on the lights or any devices, hence the action of "switch on."
Conclusion
Thus, the correct order is:
1. Key
2. Lock
3. Door
4. Room
5. Switch on
This sequence makes sense as it follows the logical steps required to enter a room and activate the lights, making option 'D' the right choice.

There is only one occurrence of 4 in the sequence that is immediately preceded and followed by an even digit: 2 4 8.

It seems like the directions are incomplete. Could you please provide the alphabet or any additional information needed to answer the questions?

- Given: Ravi is 13th from the back and Amar is 12th from the front.
- Let's assume there are 'x' boys in the queue.
- So, the position of Hari will be (x - 12) from the back and (x - 13) from the front.
- Since Hari is standing between Ravi and Amar, we have:
- (x - 13) - Ravi's position = Ravi's position - 1
- Ravi's position - (x - 12) = Amar's position - 1
- Solving the equations, we get Ravi's position as 13 and Amar's position as 14.
- Therefore, the minimum number of boys standing in the queue should be 14.

Therefore, the correct answer is option 'A' (14 boys).