Bunuel
The first cyclist from point A and the second cyclist from point B simultaneously started moving toward each other, at their respective constant speeds. They met each other after 36 minutes and continued moving without stopping. After the meeting, the first cyclist doubled his speed, and the second cyclist reduced his speed by 10%. The first cyclist reached point B 6 minutes after the second cyclist reached point A. How much time did the first cyclist take to travel from point A to point B ?
A. 1 hour
B. 1 hour and 4 minutes
C. 1 hour and 6 minutes
D. 1 hour and 10 minutes
E. 1 hour and 36 minutes
Let the meeting point between A and B is P
Also, let the cyclist from A be named X and the one from B be named Y
X covered AP in 36 min, Y covered BP in 36 min
Let A would have covered PB in x min, but at twice his speed, he will take x/2 min
Let B would have covered PA in y min, but at 90% of his speed, he will take y/0.9 = 10y/9 min
Thus: x/2 = 6 + 10y/9 ... (i)
Also, X covered AP in 36 min and BP in x min (usual speed)
Y covered BP in 36 min and AP in y min (usual speed)
=> speed ratio = 36/y = x/36 => y = 1296/x
From (i): x/2 = 6 + 1440/x
=> 1440/x = 6 + x/2
Solving, we get: x = 60
Thus, actual time taken = x/2 = 30 mins to cover PB
Thus, total time = 36 + 30 = 66 min
Answer C