Can you find the missing piece of the Porsche?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

15 caves are arranged in a circle at the temple of doom. One of these caves has the treasure of gems and wealth. Each day the treasure keepers can move the treasure to an adjacent cave or can keep it in the same cave. Every day two treasure seekers visit the place and have enough time to enter any two caves of their choice.

How do the treasure seekers ensure that they find the treasure in the minimum number of possible days?

What has no start, end, or centre?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

Can you place three balls such that the equation shown in the picture holds true?

What's the best place to go shopping in the ocean?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?