A is 100m away from headquarters. B is 8m away from headquarters. A runs twice as fast as B. How far away from headquarters will B be when A arrives at headquarters.

Question

A is 100m away from headquarters.  B is 8m away from headquarters.  A runs twice as fast as B.  How far away from headquarters will B be when A arrives at headquarters.

I drew a number line and did a jump of 16 for A and a jump of 8 for B.  This brings A to 84m away and B is at HQ.  Why B continues to run, I have no idea, but then I did a jump of 84m for A bringing A to HQ and then B moves 42m away from HQ.  I've tried other ways and keep arriving at the same answer, but the correct answer is supposed to be 30...what am I doing wrong?

Damon · Answer

I bet B starts at 80, not 8 and runs at speed v A runs at speed 2v t = 100/2v Bdistance run = v t = v(100/2v) = 50 so B is still 80 - 50 = 30 meters away

wendy · Answer

I agree...thanks, Damon. I'm calling a typo on this question and not going to worry about it anymore.