Solution: (1) A school draws 1 10× =60 people, and B school draws 1 10× =50 people, so x= 10, y=7,

(2) It is estimated that the excellent rate of A school is 0, and that of B school is 40%.

(Ⅲ)

k 2 = ≈2.83>2.706

Because 1-0. 10 = 0.9,

Therefore, there is a 90% certainty that the math scores of the two schools are different.