Replace the question mark with the correct number below.

A blonde put eyeliner on her head. Why?

There was a strange boy who was born before his father. How can this be possible?

Using mathematical symbols like +, -, and x in order to make the equations correct. Replace # with the above-given symbols.

9 # 8 # 7 # 6 # 5 # 4 = 91

Can you start the fire using two pieces of wood?

What makes this number unique: 8,549,176,320?

There is a hypothetical state between the USA and Mexico border 'Tango'.
Here 70 percent of the population have defective eyesight, 75 percent are hard of hearing, 80 percent have Nose trouble and 85 percent suffer from allergies, what percentage (at a minimum) suffer from all four ailments?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

You’re out on the water and see a boat filled with people. You look away for a second and look back again, but this time you don’t see a single person on the boat. Why? Hint: The boat did not sink.

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?