Here is a mathematical expression that also secretly tells a movie name. What movie is that?

What four weights can be used to balance from 1 to 30 pounds?

What has 88 keys?

Divide 110 into two parts so that one will be 150 per cent of the other. What are the 2 numbers?

What number do you get when you multiply all of the numbers on a telephone's number pad?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

People make me, save me, change me, raise me. What am I?