Can you replace the question mark with the correct number?

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 ()

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?

Which is the smallest number that you can write using all the vowels exactly once?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

In the image given, you can find several triangles. Can you count them all?

John has played 50 ODI's and his average is 50. How many runs should he score in his 51st ODI, so that his average score jumps to 51?

Can you name some countries which do not have the alphabet 'A' in them?

In a football game, Christina defeated Teresa by 2 - 0 but no man from either side scored. How can this be possible?

Can you count the number of squares in the figure below?