Can you name some countries which do not have the alphabet 'A' in them?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

what does this picture(rebus) riddle means ?

What is the next number?

77, 49, 36, 18 ?

You need to arrange three 7 and mathematical symbols to form number 1?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?

Can you solve the below tricky visual equation?

Which word does the below Plexor means ?