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A spin-1/2 particle is in state ∣ψ⟩=(1/5)∣↑z⟩+(2/5)∣↓z⟩|\psi\rangle = (1/\sqrt{5})|{\uparrow_z}\rangle + (2/\sqrt{5})|{\downarrow_z}\rangle. First SxS_x is measured and the +ℏ/2+\hbar/2 outcome is obtained (collapsing to ∣+x⟩=(1/2)(∣↑z⟩+∣↓z⟩)|{+x}\rangle = (1/\sqrt{2})(|{\uparrow_z}\rangle + |{\downarrow_z}\rangle)), then SzS_z is measured. With ⟨+x∣ψ⟩=3/10\langle{+x}|\psi\rangle = 3/\sqrt{10} and ⟨↑z∣+x⟩=1/2\langle{\uparrow_z}|{+x}\rangle = 1/\sqrt{2}, what is the joint probability of getting Sx=+ℏ/2S_x = +\hbar/2 followed by Sz=+ℏ/2S_z = +\hbar/2?