If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

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?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

Do You See It?