# RE8 | openai/gpt-5.4-mini | run 1

## Prompt

Minimize total time to finish these tasks, one at a time, respecting dependencies: A (2h, no deps); B (3h, needs A); C (1h, no deps); D (2h, needs B and C). Give a valid order and the total time.

## Response

The fastest valid schedule is to do **A and C first**, then **B**, then **D**. Because **B** depends on **A** and **D** depends on both **B** and **C**, the minimum total completion time is **7 hours**.

## One valid order
- **A** (2h)
- **C** (1h)
- **B** (3h)
- **D** (2h)

## Why this is minimal
- **A** and **C** can start immediately.
- **B** can only start after **A** finishes.
- **D** can only start after both **B** and **C** finish.
- The critical path is **A \(\rightarrow\) B \(\rightarrow\) D = 2 + 3 + 2 = 7 hours**.

Would you like me to also show the earliest-start timeline for each task?
