1. The problem statement, all variables and given/known data A particle is moving in one dimension, estimate the number of quantum states available to that particle if it is an electron confined in a region 10-9m long with speed less than 107 m/s (less than meaning velocity is between 107 and -107 m/s) 2. Relevant equations [x][px]/h x being the total accessible area in phase space px being the particle's momentum h being Plank's constant 3. The attempt at a solution This seemed pretty straight forward. I plugged in the values the question gives x = 10-9 I broke down px into mvx and plugged in the value of those given in the problem. I plugged in 107 for vx, even though it's "less than" that value. I just made up for that by making my answer "number of quantum states ≤ 13.7", which is my answer. Now the answer in the solution manual (no solution provided) gives an answer of 27. I'm thinking something is wrong with the velocity part. And are those brackets supposed to mean "expectation value"? Thanks.