physics
posted by Sandhya .
Design some simple digital circuits based on Boolean expressions. Draw circuits that implement the following Boolean expressions using some combination of AND, OR, NOT, NAND, and NOR gates.
 NOT X OR NOT Y OR Z
 X OR Y OR NOT Z
 NOT X AND Y OR NOT Y AND Z
Write a two to three page paper discussing your design. Please include the following:
1. Diagrams of your logic circuits.
2. Truth tables that indicate the output (a 0 or a 1) for each possible combination of values of X, Y, and Z.

This is one of those where you need to post your suggestions and we will comment. From a personal point of view I like to convert the words into a Boolean symbols expression before I do anything else. You may have done the reverse to post it here, of course.
If it is useful there are truth tables for the various gates here:
http://en.wikipedia.org/wiki/Logic_gate
It is not clear in your question if you can use multiple input gates, such as 3input OR Gates?