Problem 9 has some typos.

[jaeyoo]

1-(c). Projectors are $|0\rangle\langle0|$ and $|1\rangle\langle1|$. However, it says $|0\rangle\langle0|$ and $|0\rangle\langle1|$. Also, it says the same thing twice. p(0) = \langle\psi|\Pi_0\psi\rangle and p(0) = \langle\psi|\Pi_0\psi\rangle. It should be p(1) = \langle\psi|\Pi_1\psi\rangle

3-(a) The problem seems to be about solving on <XY> but suddenly <XZ> appears. Is it intended? where is 3-(b)?

[rmlarose]

Thanks @jaeyoo for pointing these out! Will fix now.