A man covers a distance of 22 km in 4 hours by initially walking and then…
2020
A man covers a distance of 22 km in 4 hours by initially walking and then jogging at speeds of 4 km/hour and 10 km/hour, respectively. The distance covered by him during walking is
- A.
10 km
- B.
12 km
- C.
15 km
- D.
18 km
Attempted by 4 students.
Show answer & explanation
Correct answer: B
Let the distance covered while walking be x km.
Walking speed = 4 km/hour, so walking time = x/4 hours.
The remaining distance is 22 - x km. Jogging speed = 10 km/hour, so jogging time = (22 - x)/10 hours.
Total time is 4 hours:
x/4 + (22 - x)/10 = 4
Multiplying by 20:
5x + 2(22 - x) = 80
5x + 44 - 2x = 80
3x = 36
x = 12
Therefore, the distance covered during walking is 12 km.