If it took eight men ten hours to build a wall, how long would it take four men to build it?

Find out the missing number in the picture attached:

A time long back, there lived a king who ruled the great kingdom of Trojan House. As a part of the renovation of the kingdom to meet future security needs, he asked his chief architect to lay down a new play in a manner that all of his 10 castles are connected through five straight walls and each wall must connect four castles together. He also asked the architect that at least one of his castles should be protected with walls. The architect could not come up with any solution that served all of King's choices, but he suggested the best plan that you can see in the picture below. Can you find a better solution to serve the king's demand?

why number 8549176320 is one of a kind?

Thirty friends were on a hiking trip when they decided to enjoy the bonfire. They assembled for it and agreed to play a game. For that, they divided themselves into five teams with seven members each, forming five rows.

How did they manage to achieve this formation?

My location can be determined by the below rebus.
So where am i ?

Forwards I am heavy, backward I am not. What am I?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

As we know that white starts the game of chess. Can you find the scenario shown in the picture below is possible when all the white pieces are at the original place while the black pawn is not as in the below picture?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?