The weather in Nanchang in May

(1) Let "take any vote from all the votes and get the vote that does not support investment" as event a,

From the known P(A)=y+30 100=25,

So y= 10, B=40, x=40, A=60? ... 6 points

(2)x2= 100×(30×40？ 20× 10)250×50×40×60≈ 16.67>6.635,

Therefore, it is at least 99% sure that the rainstorm in Nanchang is related to whether the people agree to increase the investment in urban underground drainage facilities ... (12 points)