Three cyclists: A, B, C start simultaneously from P towards Q. On reaching Q, they turn back and cycle towards the starting point. On her way back, C meets B and A at a distance of 30km and 70 km respectively from Q, while B on her way back meets A at a distance of 42 km from Q.
- What is the speed of A & C, given B's speed is 18km?
- What is the total distance between P & Q.?
Now my approach is something like this:
Taking B's case,
Before B meets A,
B traveled 30+42=72 km, at a speed of 18km/hr. In the same time, A traveled 70-42=28 km. So Speed of A is 28/4= 7 km/hr.
However this is wrong, the speed of A is 12 km/hr.
I did it in a different way using ratios of speed and distance and got the right answer but the process was quite lengthy and needed lots of calculation.
However, my biggest question is why is my original method wrong? Where am I doing the mistake?