A person travels equal distances with speeds of 3 km/hr, 4 km/hr and 8 km/hr, respectively, and takes a total of 425 minutes. What is the total distance (in km) travelled?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e 30.
Let the equal distance for each part = x km
Total distance = 3x
Total time taken = 425 minutes = 425/60 = 85/12 hours
Time1 = 3x, Time2 = 4x, Time3 = 8x
Total time = x/3 + x/4 + x/8 = 85/12
⇒ 8x/24 + 6x/24 + 3x/24 = 85/12 ⇒ (8x + 6x + 3x)/24 = 85/12 ⇒ 17x/24 = 85/12
x = 85/12 × 24/17 = 2040/204 = 10
Total distance = 3x = 3 × 10 = 30 km