在10件产品中有2件次品，任意抽取3件，则抽到次品个数的数学期望的值是_____

Hello, everyone. Here is something important for everyone going to London next month. As you know, you are going to stay with a family for two weeks. Now, the most important thing is money. You should take about $530 with you. I think it will be enough for everyone. Then, when you arrive, your new family will meet you. You must remember to wear a red shirt, so the family will find you easily. They’ve been told you all wear red shirts. You’ll also need to take with you 4 photos of yourself and, of course, it’s very important that you take the school letter. While you’re there, if you have any problems, you can call Leech School Office. I’ll give you the office phone number now: it’s 580-4436 and the person to ask for is Mrs. Belcher…She’s in the office from nine o’clock in the morning until five in the afternoon every day. OK. That’s everything. Have a good journey!

Where are they going?	1.
How long are they going to stay there?	2.
Why must they wear red shirts?	3.
What’s the school office telephone number?	4.
What could Mrs. Belcher’s job be according to the reading?	5.