What four weights can be used to balance from 1 to 30 pounds?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

Can you complete the sequence puzzle?

AR TA GE CA LE VI LI _

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

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

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?