Which tank will fill first?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

What does the below rebus puzzle mean?

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

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

Birbal was jester, counsellor, and fool to the great Moghul emperor, Akbar.
The villagers loved to talk of Birbal's wisdom and cleverness,
and the emperor loved to try to outsmart him.
One day Akbar (emperor) drew a line across the floor.
"Birbal," he ordered, "you must make this line shorter, but you cannot erase any bit of it."
Everyone present thought the emperor had finally outsmarted Birbal.
It was clearly an impossible task.
Yet within moments the emperor and everyone else present had to agree that Birbal had made the line shorter without erasing any of it.
How could this be?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

What is both possible and impossible at the same time?