Translate the following inference to logic notation: There is at least one x for which z will make tea. For all x, z is happy. For all x, z will make tea if and only if z is an electrician. Therefore there is at least one x for which z is happy and z is an electrician.
exists x: P(x). forall x: Q(x). forall x: P(x) <-> R(x). Therefore exists x: Q(x) and R(x).