What goes up but never comes down?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

What has many keys but can’t open a single lock?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

Find the hidden tiger in the given optical illusion ?

The dirtier I get, the whiter I look. Who am I?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

Can you solve the equation by finding the value of
A) Horse
B) Cowboy boot
C) Horseshoe

In the Picture?

A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?