A drunkard walking in a narrow lane takes 5 steps forward and 3 steps backward, followed again 5 steps forward and 3 steps backward, and so on. Each step is 1 m long and requires 1 s. Determine how long the drunkard takes to fall in a pit 13 m away from the start.

The effective distance travelled by drunkard in 8 steps = 5-3 = 2m

Therefore, he takes 32 steps to move 8 m.

Now, he will have to cover 5 m more to reach the pit , for which he has to take only 5 forward steps.

Therefore, he will have to take = 32 + 5 = 37 steps to move 13 m. Thus, he will fall into the pit after taking 37 steps i.e. after 37 s from the start.