What is the economic term for the amount of something available and the demand for goods?

The term "quantity supplied" refers to the amount of available product. For instance, if a farmer provides 100 bushels of corn, then this is the quantity supplied of corn.

On the other side, the term "quantity demanded" refers to the amount of items people are willing and able to pay for. Both components must be present. If someone is willing to pay for something, but not able to, then this isn't part of the demand equation. Likewise, if they have the money, but don't want the product, then it doesn't make sense to include this as part of demand either.

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation: