The problem asks us to determine the position of six delivery boys arranged in a row based on several clues. We need to figure out their exact sequence from left to right or right to left and then identify the boy at the fourth position from the right end of the row.

Understanding the Delivery Boy Arrangement Clues

Let's break down the given clues about the arrangement of the six delivery boys: U, V, W, X, Y, and Z.

• Z is to the immediate left of W. This tells us that Z and W are next to each other in the sequence, with Z coming just before W. We can represent this part of the sequence as Z W.
• Z and Y are at the extreme ends of the row. This means either Z is the first person from the left end and Y is the last person from the right end, or vice versa. The row has 6 positions.
• W is exactly between Z and V. Since we know Z is immediately to the left of W (Z W), for W to be exactly between Z and V, V must be immediately to the right of W. This extends our known sequence part to Z W V.
• U is to the immediate left of X. This gives us another pair sequence: U X.
• Y is to the immediate right of X. This means X and Y are next to each other, with Y coming just after X. We can represent this as X Y.

Building the Delivery Boy Sequence

We have several fragments of the sequence:

• Fragment 1: Z W V (derived from the first and third clues)
• Fragment 2: U X (from the fourth clue)
• Fragment 3: X Y (from the fifth clue)

Combining Fragments 2 and 3, we see that X is followed by Y, and U is immediately before X. This gives us the sequence U X Y.

Now, let's use the clue that Z and Y are at the extreme ends. We have the sequence Z W V starting with Z, and the sequence U X Y ending with Y.

Since there are 6 delivery boys, these two sequences must combine to form the complete row of 6. The first sequence Z W V accounts for 3 boys starting from Z. The second sequence U X Y accounts for 3 boys ending with Y.

Let's place them together, assuming Z is at the left end and Y is at the right end:

Position 1 | Position 2 | Position 3 | Position 4 | Position 5 | Position 6

Based on Z W V: Z is at 1, W is at 2, V is at 3.

Based on U X Y and Y being at the end (position 6): Y is at 6, X is at 5 (immediate left of Y), and U is at 4 (immediate left of X).

Putting it all together, the arrangement from left to right is:

Z W V U X Y

Verifying the Arrangement

Let's check if this arrangement satisfies all the given conditions:

• Z is to the immediate left of W? Yes, Z W.
• Z and Y are at the extreme ends? Yes, Z is first, Y is last.
• W is exactly between Z and V? Yes, Z W V.
• U is to the immediate left of X? Yes, U X.
• Y is to the immediate right of X? Yes, X Y.

All conditions are met. The arrangement of the delivery boys from left to right is Z, W, V, U, X, Y.

Finding the Fourth Position from the Right

The row is Z W V U X Y. We need to find the delivery boy at the fourth position starting from the right end.

Let's list the positions from the right:

• 1st from right: Y
• 2nd from right: X
• 3rd from right: U
• 4th from right: V

Alternatively, we can look at the table of positions:

Looking at the table, the delivery boy at the 4th position from the right is V.

Conclusion

By carefully using each clue to build the sequence of the delivery boys in the row, we found the arrangement to be Z W V U X Y from left to right. Counting four positions from the right end (Y is 1st from right), we find that V is at the fourth position.

The delivery boy at the fourth position from the right is V.

Revision Table: Delivery Boy Arrangement

Review the key steps to solving this delivery boy arrangement puzzle.

Additional Information: Linear Arrangement Puzzles

Linear arrangement puzzles are a common type of logical reasoning question. They involve arranging people or objects in a straight line based on a set of conditions. Key strategies include:

• Representing relationships: Use symbols or short forms to represent conditions (e.g., Z W for Z is left of W).
• Identifying fixed positions: Look for clues that fix someone's position (like being at an end).
• Combining fragments: Piece together smaller known sequences.
• Checking constraints: Ensure the final arrangement satisfies all given conditions.
• Counting from specific ends: Pay close attention to whether positions are counted from the left or the right.

These puzzles test your ability to logically deduce the overall structure from partial information.