Why are all black people so quick ?

A mathematics teacher took exams for his students. Out of the total students, 25% passed both the tests included in the exam. However, only 42% were able to clear the first test.

Can you find out the percentage of those students who passed the first test and also passed the second test?

Take one out and scratch my head, I am now black but once was red. What am I?

What has many keys but can’t open a single lock?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

What is the word or phrase?

Why is the Hole below a Lock?

Can it be possible to build a house that has all its four walls facing towards the South?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

On a charity event in Russia, Murray beat Djokovic by winning six games and losing three games.
Note: There is a total of 5 service breaks(one who serve lost the game).
Who served first, Djokovic or Murray?