A car runs 10,000 miles using 5 tyres interchangeably. To have equal wear on…
2025
A car runs 10,000 miles using 5 tyres interchangeably. To have equal wear on all tyres, how many miles should each tyre have run?
Answer: B. 8000 — Concept: When a car uses a fixed number of tyres at any moment but rotates among a larger set so every tyre wears out equally, the total wear (in tyre-miles)…
- A.
5000
- B.
8000
- C.
4000
- D.
3000
Attempted by 69 students.
Show answer & explanation
Correct answer: B
Concept: When a car uses a fixed number of tyres at any moment but rotates among a larger set so every tyre wears out equally, the total wear (in tyre-miles) equals the distance travelled multiplied by the number of tyres in use at once; sharing that total equally across all available tyres gives the mileage each individual tyre runs.
A car has 4 tyres bearing its weight at any instant, so travelling 10,000 miles produces a total wear of 10,000 × 4 = 40,000 tyre-miles.
The 5 tyres are rotated interchangeably so that this total wear is shared equally among all of them.
Each tyre's share = 40,000 ÷ 5 = 8,000 miles.
Cross-check: If each of the 5 tyres runs 8,000 miles, the total wear produced is 5 × 8,000 = 40,000 tyre-miles, which matches 4 × 10,000 — confirming the calculation is consistent.
So, each tyre should have run 8,000 miles.
