Question

There are seven holes in a line. A fox can move left or right along the holes and you can watch only one hole per day. So in how many days can you catch the fox?

Answer 1

Since this is CS, have you tried writing a simulation program? You could simulate the movement of the fox using random numbers and implement the hole-watching strategy you want to test.

Answer 2

Seriously, I'm not sure you can answer that question without more information. How often does the fox move? Is it a smart fox (e.g. it goes back-and-forth between the two left-most holes) or are its movements purely random?

Answer 3

if fox is purely random and 'looks' are purely random you would expect to see fox once every 7 days on average.

Answer 4

In fact, the results are the same if the holes are in a circle or if the fox can choose any hole at random. The sample is always 7. There is always a 1/7 chance of success every time you look.