perplexus.info :: Just Math : Four cars

Four cars (Posted on 2008-06-09)

Four cars travel at constant speed along a road. Three of them (A, B and C) travel in one direction, and the fourth, D, in the opposite direction.

Car A passes B and C at 9:00h and 10:00h, respectively, and crosses car D at 11:00h.

Car D crosses car B and car C at 13:00h and 15:00h, respectively.

At what time did car B pass car C?

Bonus point: can you solve this geometrically?

Submitted by pcbouhid

Rating: 4.2500 (4 votes)

Solution: (Hide)

Both the analytical solution and the geometric solution can be found in the comments. The later is more easily achieved if we make car C stationary, and all the others trajectories relative to it.

Car B passed car C at 11:40h.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Answer	K Sengupta	2022-12-21 02:05:38
re(3): Geometric Solution -SAME HERE	pcbouhid	2008-06-11 15:32:37
re(2): Geometric Solution -SAME HERE	Ady TZIDON	2008-06-10 16:18:12
re: Geometric Solution	pcbouhid	2008-06-10 09:07:29
Geometric Solution	Robby Goetschalckx	2008-06-10 06:39:29
Solution	Bractals	2008-06-09 18:37:04
solution	Charlie	2008-06-09 13:40:19

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