I’m tall when I’m young, and I’m short when I’m old. What am I?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

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

ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

Why 1729 is a magic number? Answer Logically.

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

In which direction should the missing arrow point?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?