I started climbing up the hill at 6 a.m. and reached the temple at the top at 6 p.m. Next day I started coming down at $6$ a.m. and reached the foothill at $6$ p.m. I walked on the same road. The road is so short that only one person can walk on it. Although I varied my pace on my way, I never stopped on my way. Then which of the following must be true?
- My average speed downhill was greater than that uphill.
- At noon, I was at the same spot on both the days.
- There must be a point where I reached at the same time on both the days.
- There cannot be a spot where I reached at the same time on both the days.