What number do you get when you multiply all of the numbers on a telephone's number pad?

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

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

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 want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

What does this rebus puzzle means ?