How many studnets are allergic to milk?
select count(*) from has_allergy as t1 join student as t2 on t1.stuid = t2.stuid where t1.allergy = "Milk"
How many are allergic to that or to eggs?
select count(*) from has_allergy as t1 join student as t2 on t1.stuid = t2.stuid where t1.allergy = "Milk" or t1.allergy = "Eggs"
Of those, how many are female?
select count(*) from has_allergy as t1 join student as t2 on t1.stuid = t2.stuid where t2.sex = "F" and t1.allergy = "Milk" or t1.allergy = "Eggs"