Read the given instructions carefully and answer the related questions:

Six experts – P, Q, R, S, T, and U – delivered presentations on six different tech gadgets – Smartwatch, Tablet, Headphones, Laptop, Drone, and Camera – one after another, but not necessarily in the same order.

Three persons presented between Q, who brought a Smartwatch, and the person who brought a Drone. U presented immediately after the person who brought a Drone. The person who brought Headphones presented two places before the person who brought a Drone. T presented immediately before P. S presented after the person who brought a Tablet but before R. The person who brought a Laptop presented before the one who brought a Camera.

Which expert presented three places after the person who presented immediately before S?

The correct answer is U.

Step-by-Step Explanation:

We are given six experts (P, Q, R, S, T, and U) who presented one after another in six sequential slots (Positions 1 to 6) with six gadgets (Smartwatch, Tablet, Headphones, Laptop, Drone, and Camera).

Let's deduce the order of presentation step-by-step based on the given clues:

1. Positions of Q, Drone, and U:
- Three persons presented between Q (who brought a Smartwatch) and the person who brought a Drone.
- U presented immediately after the person who brought a Drone.
- Since U is immediately after the Drone, the Drone cannot be in Position 6. Therefore, the Drone must be in Position 5, and U presented in Position 6.
- Counting three positions back from Position 5 (Drone), Q must be in Position 1.
• Position 1: Q (Smartwatch)
• Position 5: Drone
• Position 6: U

2. Position of Headphones:
- The person who brought Headphones presented two places before the person who brought a Drone.
- Since the Drone is at Position 5, Headphones were presented at Position 5 - 2 = 3.
• Position 3: Headphones

3. Arranging Experts (T, P, S, and R):
- T presented immediately before P, which means T and P occupy consecutive positions.
- S presented after the person who brought a Tablet, but before R (Tablet < S < R).
- The remaining empty positions for experts are 2, 3, 4, and 5.
- S cannot be in Position 2, because Tablet must come before S, but Position 1 is already taken by Smartwatch. Therefore, Tablet must be at Position 2.
- This places T in Position 2 and P in Position 3.
- With S coming before R, S must be at Position 4 and R at Position 5.
• Position 2: T (Tablet)
• Position 3: P (Headphones)
• Position 4: S
• Position 5: R (Drone)

4. Remaining Gadgets (Laptop and Camera):
- The person who brought a Laptop presented before the one who brought a Camera.
- The available gadget slots are Positions 4 and 6. Hence, Laptop is at Position 4 and Camera is at Position 6.
• Position 4: S (Laptop)
• Position 6: U (Camera)

Final Order of Presentation:
1. Position 1: Q (Smartwatch)
2. Position 2: T (Tablet)
3. Position 3: P (Headphones)
4. Position 4: S (Laptop)
5. Position 5: R (Drone)
6. Position 6: U (Camera)

Answering the Question:
- S presented in Position 4. The person who presented immediately before S is at Position 3, which is P.
- Three places after Position 3 is Position 3 + 3 = 6.
- The expert at Position 6 is U.