Can you count the number of triangles in the picture below?

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

In a secret society, a buried chamber can be accessed only via a secret password. The password is seven characters long and comprises of just letters and numbers.

You find a code that can help you in cracking the password. The code says "You force heaven to be empty".

Can you deduce the password from that?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Consider this about a word: The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

The more of this there is, the less you see. What is it?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?