Stopping distance increases with reduced tire grip and road wetness

Steps:

• Identify baseline: Dry road with new tires has shortest stopping distance due to maximum friction.
• Compare conditions: Old tires reduce grip, increasing distance slightly; wet road reduces friction more significantly, especially with old tires.
• Locate dry old tires: This should yield distances longer than dry new but shorter than wet scenarios.
• Match options: X and Y fall between dry new (shortest) and wet new/old (longest), fitting dry old tires.

Why B is correct:

• X and Y align with expected moderate increase from tire wear alone, per friction coefficient in stopping distance formula $d = \frac{v^2}{2\mu g}$, where $\mu$ decreases mildly for old tires on dry road.

Why the others are wrong:

• A: W is too short (matches new tires); X is plausible but unpaired correctly.
• C: X fits, but Z is too long (matches wet old tires).
• D: Y and Z both too long for dry conditions.

Final answer: B