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

What's a single-digit number with no value?

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?

By using 'because' continuously three times, can you make an English statement ?

What is greater than gold but cannot be bought. it can never be sold and can earn if its sought. though it can be broken, it can still be fixed. for by birth it can't start nor by death it is ended.what am i?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

Count the number of triangles in the picture below:

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?