Professor Layton and the Diabolical Box

Puzzle 109: Walking the Dog

Original diagram for Puzzle 109: Walking the Dog

A dog dashes back and forth between a girl and her dad until he catches up, so how far does it run?

Chapter
Chapter 6
Location
West Y-Road · Lila
Picarats
50 picarats
Type
Write Answer
Region
Same in all versions
Hint 1: A gentle nudge. Tap to flip.
Hint 1

Don't try to add up every trip back and forth.

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Hint 2: The key idea. Unlocks after the previous card is flipped.
Hint 2

Work out how long the dog is running, not where it goes.

Tap to flip back
Hint 3: Almost there. Unlocks after the previous card is flipped.
Hint 3

How big is the girl's head start, and how fast does the dad close the gap?

Tap to flip back
Answer: See the answer. Unlocks after the previous card is flipped.
Answer

The answer is 50 feet.

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Solution, FAQ and sources

Solution

1. In her first 10 seconds the girl walks 10 feet, so that's her lead when the dad starts. 2. The dad gains 2 − 1 = 1 foot per second, so he catches her in 10 seconds. 3. The dog runs the whole 10 seconds at 5 feet per second.

10 × 5 = **50 feet**. The back-and-forth doesn't matter, only how long the dog runs.

About this puzzle

A girl walks for 10 seconds carrying her dog, then her dad comes out after her. She puts the dog down and keeps walking. The dog runs to the dad, back to the girl, and so on, until the dad catches her up. The girl walks at 1 foot per second, the dad at 2 and the dog runs at 5. How far does the dog run?

Unofficial fan guide, not affiliated with LEVEL-5 or Nintendo. Puzzle description, hints and solution written by Hint by Hint.

Similar puzzles: Puzzle 112: Turn On the Light, Puzzle 113: A Stack of Dice, Puzzle 071: How Old Is She?, Puzzle 111: How Many Turns?

All Professor Layton and the Diabolical Box puzzles

FAQ

What is the answer to Puzzle 109, Walking the Dog, in Professor Layton and the Diabolical Box?

The answer is 50 feet.

Where do you find Puzzle 109 in Diabolical Box?

Puzzle 109 appears in Chapter 6, in the West Y-Road area, when you talk to Lila.

How many picarats is Diabolical Box Puzzle 109 worth?

50 picarats.

Sources

Facts checked on November 14, 2026

Unofficial fan guide. Not affiliated with, endorsed by, or sponsored by LEVEL-5 Inc. Professor Layton, The New World of Steam, and all related names, characters, and trademarks are the property of their respective owners.