What does does this rebus picture means ?

What is black when you buy it, red when you use it, and gray when you throw it away?

Two natural numbers have a sum of less than 100 and are greater than one.

John knows the product of the numbers and Jacob knows the sum of numbers.

The following conversation takes place between them:
John: 'I am not aware of those numbers.'
Jacob: 'I knew you wouldn't be. I am not aware myself.'
John: 'Now I know them!'
Jacob: 'Now I know them, too!'

What are the two numbers?

What does this Rebus Picture mean?

If two fifty-foot ropes are suspended from a forty-foot ceiling that is twenty feet apart, how much rope will you be able to steal if you have a knife?

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

Where do you go to learn how to make ice cream?

I cannot talk, but I always reply when spoken to. What am I?

A Shopkeeper sold a few chickens to four different customers on a particular day. It was such that each customer purchased half of the remaining chickens and half the chicken more.

Can you find out how many chicken were sold by the shopkeeper on that day if we tell you that the fourth customer bought a single chicken ?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.