1. An insurance company has a paper record and an electronic record for every policy it has. For 60% of the paper records that containing errors, the corresponding electronic records containing error. For 75% of the electronic records that containing errors, the corresponding paper records containing error. The records contaning errors for both paper format and electronic format are 3% of the total policy. Ask what is the probability for the policy that does not contain errors in either paper or electronic format. 答案应该是94%吧.
2. 本月高频DS: 300 人参加health club, 1/3 swim, 2/3 tennis, 3/10 aerobics 详细参见之前的机经.
3. PS. A1 = 65, A2 = 66, A3 = 67 For k > 3, An = 8+Ak-3. 然后给5个大数, 792, 80x, 8xx, 9xx, 102x, 问哪个会属于此数列.
4. PS. 某女 salary S, tax T, after tax deposit D to savings account, then donate C to charity. Asking how much left.
5. DS. Car dealer 有三种颜色车, 白, 红, 黑, 车型大, 中, 小. 共40辆. 问有多少大型白车. a) 红, 黑车只有中型和小型. 共有19 辆 b)大型车多于中,小型车之和.
6. PS. Helen has red marble, George has blue marble, the total red marbles weighs 17%(or 13% dont remember) more than the total blue marbles. The number of red marble is 10% less than that of blue marbles. Ask what percent each red marble weighs more than each blue marbles. | 
