Why is Saturday stronger than Monday?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

What is at the end of a rainbow?

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

A bank customer had $100 in his account. He then made 6 withdrawals. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
$50 $50
$25 $25
$10 $15
$8 $7
$5 $2
$2 $0
----- -----
$100 $99

Why are the Totals not tallying?

The Little ant seems to be always confused. Do you know why?