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

Keyboard words are not in alphabetical order, Why?

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 is the Hole below a Lock?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

John, a 5-year-old boy, was really fond of the chocolates. He asked his Mother to give him some money to buy his favourite chocolates. His Mother gave him $45. He went to the shopkeeper and asked, "How much is one chocolate for?". The shopkeeper said $3 for one chocolate. Also, if you give me the wrappers of three chocolates, I will give you one for the exchange.
In total, how much chocolate could John eat?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Find the missing number in the image below.

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.