How can you tell a raw egg from a hard-boiled egg?

A boy and his father are caught in a traffic accident, and the father dies. Immediately the boy is rushed to a hospital, suffering from injuries. But the attending surgeon at the hospital, upon seeing the boy, says 'I cannot operate. This boy is my son.' How is this situation explained?

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.

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

What jumps when it walks and sits when it stands?

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.