The ratio of the distance between two places A and B to the distance between places B and C is 3 : 5. A man travels from A to B at a speed of x km/h and from B to C at a speed of 50 km/h. If his average speed for the entire journey is 40km/h, then what is the value of (x-10):(x+1)?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 20 : 31
Average speed = (total distance)/(total time)
Let the distance between A and B and B and C be 3a and 5a.
Total distance = 3a + 5a = 8a.
Total time = 3a/x + 5a/50
According to the question,
40 = (8a)/(3a/x + 5a/50)
40ax = 600a + 20ax
x = 30
(x - 10) : (x + 1) = 20 : 31.