Replace the question mark with the correct number below.

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

Can you solve below mathematical equation?

2^1234 - 2^1233

Can you place six matchsticks in a manner that each of the matchsticks is in touch with the other five matchsticks?

A spy was in Canada trying to steal insider information on how to set up new Maple Syrup factories in their country. He was introduced to the operations manager of the biggest factory in Canada. However, the manager was suspicious and decided to test him with a question before he trusted him. So he asked, “What would you be sure to find in the middle of Toronto?” The spy thought fast and came up with an answer for the manager. What was his answer?

What word does this rebus represent?

meta meta
meta meta

Solve the counting riddle by identifying the number of triangles in the given picture.

Solve the puzzle by telling what does below picture means.

What building has the most stories?