2022 · Q30
A runner’s average speed reduces by 25% every hour. If he runs 16 km in the first hour and he runs for 3 hours, then what is his overall average speed?
general-mental-abilityquantitative-aptitude
- A12 km/hr
- B12.33 km/hr
- C10.33 km/hr
- D13 km/hr
Explanation
The runner covers 16 km in the first hour. With speed reducing 25% each hour, the second hour's distance is 16 × 0.75 = 12 km, and the third hour's is 12 × 0.75 = 9 km. Total distance = 16 + 12 + 9 = 37 km over 3 hours. Overall average speed = 37/3 ≈ 12.33 km/hr. Hence option B.