Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

A father's child, a mother's child, yet no one's son.

Who am I?

Can you decipher the two rows to find the hidden word?

What do you think with the below Picture ?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

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

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

Can you count the number of triangles in the picture below?

Why is a river so rich ?