Question: i need help in the following math questions 2 bit...

I need help in the following math questions:

2. Bit strings are "words" where every character is a 0 or a 1. Example: 011101 is a bit string of length 6.

2A. How many bit strings are there of length 50?

2B. How many of those bit strings (of length) start with a 1 and end with 00?

2C. How many big strings are there with length 6 to 8?