快猫短视频

#231 Bark run

Set by Howard Williams

My dog, Zippy, can鈥檛 wait for me to take him for a walk. I say 鈥渨alk鈥�, but it is only me that does the walking.

As soon as we get through the gate into the field to begin his exercise, I unclip Zippy鈥檚 lead and he bounds off straight to the other end 200 metres away while I stroll along the path directly towards him.

As soon as he gets to the far end, he turns round and hurtles back again, brushing past me on his way to the gate where he waits for me to put his lead back on. I, of course, reverse direction as soon as he passes me on the return leg.

I have figured out that, while in the field, Zippy runs three times as fast as I walk. How far do I walk in the field?

Solution next week

#230 Train of thought

Solution

There are seven stations. Each is visited twice, except for the station at the end of the line, halfway through the journey. So, for six of the stations we just have to make one of two choices: to take the photo on the way out or on the return.

This yields 2脳2脳2脳2脳2脳2 = 64 possible photo orders.