Mohit goes to his office at the speed of 10 m/s and returns to his home at the speed of x km/hr. If average speed of Mohit for the whole journey is 12 m/s, then what is the value of x?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 54 km/hr
Average speed = 2ab/(a + b)
Where, a = speed of Mohit going to office
b = speed of Mohit returning from office
12 = 2 × 10 × x/(10 + x)
120 + 12x = 20x
8x = 120 = ,x = 15Km/h
15 × 18/5 = 54m/s