Can you find out which number multiplied by itself will give the output as 12345678987654321?

I make two people out of one. What am I?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

Which English verb becomes past tense just by rearranging the letters?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

What does it mean?

Can you spot the man between the coffee bean in the picture below ?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?