why number 8549176320 is one of a kind?

Jack have ten pairs of black socks, eight pairs of white socks and seven pairs of green socks. Everything is mixed in a draw. As there is no light he were not able to identify the colour of the socks. How many of the socks did he want to take to match one pair

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

There are three boxes which are labeled as Rs100, Rs150, and Rs200. One box contains two notes of Rs. 50. The second box contains one note of Rs50 and one note of Rs100 The third box contains two Rs. 100 notes. All boxes are labeled incorrectly.

What is the minimum number of boxes you must check in order to label all boxes correctly?

What word begins and ends with an E, but has only one letter?

Which number should replace the question mark?

Which is Odd One Out and why?

4377

3954

9862

8454

9831

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

What work can one never finish?

Buy me, smell me or deliver me, I do not change.

Who am I?