You flip three coins (a nickel, a dime, and a quarter), assigning the values of + 1 for heads (H) and - 1 for tails (T). Each outcome after flipping the three coins constitutes a microstate. How many microstates are possible by flipping these three coins?

8 possible microstates.

Explanation:

Supposed we tossed three (3) coins (a nickel, a dime, and a quarter).

The possible outcomes can be seen as follows.

Coin

1st. + 1 + 1 + 1 - 1 + 1 - 1 - 1 - 1

2nd + 1 + 1 - 1 + 1 - 1 + 1 - 1 - 1

3rd + 1 - 1 + 1 + 1 - 1 - 1 + 1 - 1

There 8 (eight) microstates are possible.