In which direction should the missing arrow point?

The dirtier I get, the whiter I look. Who am I?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

It is always ahead of me yet I can never see it. What is it?

Three people check into a hotel. They pay $60 for the rent of the room. After they check-in, the manager realize that the rent for the room is $55. So, he gives $5 to the bellboy and asks him to give it to them. The bellboy thinks that it will be difficult for the three people to share $5 among them and seeking the personal benefit, he pockets $2 and gives the remaining $3 to them.

Now, each person paid $20 and got back $1. In this manner, each of them paid just $19 which totals to the amount of $57. The bellboy has $2 with him and adding them, we get $59. So where is the remaining $1?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Find the next number in the series below

21 32 54 87 131 ?

Can you discover the missing number in this series?

37, 10, 82
29, 11, 47
96, 15, 87
42, ?, 15

One day, I thought of ways that can be used for creating a palindrome. So I decided that I will turn into a larger number by adding the reversed digits to the original number and keep doing it till I finally obtained a palindrome.

I am not sure if this process will always result in a palindrome eventually but I was able to produce a four-digit palindrome. Can you guess my starting number?

What seven-letter word has hundreds of letters in it?