Задача по теории вероятностей. Партия изделий, среди которых 9 - первого сорта, 6 - второго и 3 - третьих сорта случайным образом разбивается на 3 равные
части. Найдите вероятность того, что изделия первого, второго и
третьего сортов поделятся при этом поровну.
1 A: Linda ...is learning... (learn) to drive at the moment.
B: I know. She told me last week.
2 A: Has Alan got a job?
B: Oh yes. He … (be) the manager of a leisure centre.
3 A: Do you want to have a break now?
B: Not yet. I … (write) a report for tomorrow's meeting.
4 A: It's ten o'clock. Have you given the manager his letters?
B: Yes, and I … (also/type) six reports so far this morning.
5 A: Is Jeff still in the garden?
B: Yes. He … (plant) flowers all afternoon.
6 A: That author is very well-known, isn't she?
B: Yes. She … (write) twenty novels so far.
7 A: You look very happy today.
B: I am. I … (just/hear) some good news.
8 A: What time … (the play/start) tonight?
B: Seven o'clock, I think.
9 A: Are you new to this company?
B: Not really. In fact, I … (work) here for almost two years.
10 A: Are you ready for the concert?
B: Yes. I … (practise) for weeks.
11 A: Do you do any exercise at all?
B: Yes. Actually, I … (go) swimming three times a week.
(3 9/20+2.75):2=(3 9/20+2 3/4):2=(3 9/20+2 16/20):2=(69/20+56/20):2=(125/20):2=(125/40)=3 5/40=3.125
(33.74-5 1/25):7=(33 74/100-5 4/100):7=(3374/100-504/100):7=(2870/100):7=(2870/100)*(1/7)=(2870/700)=4 70/700=4.1
(37 1/5-6.8):8=(37 2/10-6 8/10):8=(372/10-68/10):8=(304/10):8=(304/10)*(1/8)=38:10=3.8
(14.7+23 4/5):11=(14 7/10+23 8/10):11=(147/10+238/10):11=(385/100):11=(385/100)*(1/11)=(35/100)=0.35
(61.68-4 2/25):12=(61 68/100-4 8/100):12=(6168/100-408/100):12=(5760/100):12=(5760/100)*(1/12)=(480/100)=4.8