5. A school organized a hiking activity, planning to depart from location A at 10:10 and arrive at location B at 13:10. However, they departed 5 minutes late and arrived 4 minutes early. They arrived at location C, which is between A and B, exactly on schedule. What was the arrival time at location C? ( ).
A. 11:40
B. 11:50
C. 12:00
D. 12:10
【Answer】B
【Analysis】As shown in the figure, it is equivalent to two cars $A, B$ on the same road, one driving at the original speed, and the other driving at the new speed. Therefore, leaving 5 minutes later is equivalent to $\mathrm{B}$ chasing $\mathrm{A}$, which has already driven for 5 minutes, and catching up at point C. When $\mathrm{B}$ reaches point B, $\mathrm{A}$ still has 4 minutes of travel left. This creates two pursuit problems, with the speed difference remaining constant, and the ratio of the pursuit distances is 5:4. Therefore, (distance from A to C): (distance from C to B) $=5: 4$, so the time ratio is $5: 4$, hence the choice is $\mathrm{B}$.