Part 1.

You have 10 bags of 1000 gold coins each.
One of the bags is fake gold and each coin weighs 1.1 lb.
The other bags contain real gold and each coin weighs 1.2 lb.

You have one penny to use on a penny scale.
( No tricks, using gum and a string to pull the penny back out :) )

How can you weigh the gold in such a way that you can determine which bag has the fake gold.


Part 2

This problem is the same as above, but there is at least one bag of real gold. There could be as many as 10 with real gold.

How do you weigh the gold in such a way to determine which bags have the real gold?