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

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

Replace the (?) with the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

What number divided by 4 is the same as that number minus 4?