GWD2-MATH SECTION 请教几道DS 麻烦指教

Q30:
From May 1 to May 30 in the same year ,the balance in a cheching account increased. What was the balance in the checking account on May 30？
(1) If ,during this period of time,the increase in the balance in the checking account had been 12 percent, then the balance in the account on May 30 would have been $504
(2)During this period of time,the increase in the balance in the checking account was 8 percent.

这题读不大懂 选C 麻烦指点哦

Q32：
What is the probability that  event E or event F or both will occur?
(!)The probability that event E will occur is 0.6
(2)The probability that event E will occur is 0.4

这题我怎么看也觉得选D  不知为何会选E？


Q36:
If x and y are integers,is y an even integer?
(1) 2y-x=x的平方-y的平方
(2) x is a odd integer
(2)肯定不可能，可我也觉得(1)也不可能 因为1 可以因式分解为  x(x+!)=2y(y+1)  而x(x+1)肯定是一奇一偶，相乘肯定是偶，而2y也肯定是偶，因此y+1可奇可偶，因此y 也可奇可偶，可答案选A 。实在很困惑，麻烦各位指教 o(∩_∩)o...