Question

A test has 10 true/false questions. How many different tests can be turned in to the teacher?

Answer 1

Each question has 2 possible answers. There are 10 questions. 

1 - 2 
2 - 2 
3  - 2 
4 - 2 
5 - 2 
6 - 2 
7 - 2 
8 - 2 
9 - 2 
10 2                                                                                      There can be 20 different tests. 

Answer 2

The same as the greatest number that can be written
with 10 binary bits:  1,024