How does your web browser get a file from the Internet? Your computer sends a request for the file to a web server, and the web server sends back a response. Let \( Y= \) the amount of time (in seconds) after the start of an hour at which a randomly selected What is the probability that the request is received by this server within the first 5 minutes ( 300 seconds) after the hour? 0.0014 0.083 0.11 0.25

Jim works at an Auto centre and accidentally drops 4 bad spark plugs into a box with 20 good spark plugs. a. If he selects two spark plugs at random from the box without replacement, and the first spark plug selected was a good one, what is the probability that the second spark plug is bad?

11. One letter is selected from the word "ilovemathematics". What is the probability that a " \( t \) " or an " is chosen?

In a group of people on holiday, it is established that there are: - 10 males under the age of 21 - 8 females under the age of 21 - 5 females aged between 21 and 30 - 7 males over the age of 30 Calculate the probability that, if one person is selected at random from the group this person will be: \( \begin{array}{l}\text { a) A male under the age of } 30 . \\ \text { b) A female. } \\ \text { c) A male over the age of } 21 . \\ \text { d) A person not older than } 21 . \\ \text { e) A male given that this person is over } 30 \text { years. } \\ \text { f) A female or between } 21 \text { and } 30 . \\ \text { g) A male or a female. }\end{array} \)

4. A box contains a total of 100 CDs that were manufactured on two machines. Of them, 60 were manufactured on Machine I. Of the total CDs, 15 are defective. Of the 60 CDs that were manufactured on Machine I, 9 are defective. Let \( D \) be the event that a randomly selected CD is defective, and let A be the event that a randomly selected CD was manufactured on Machine I.

3. In a class of 100 students 75 are boys and 25 are girls. The chance that a boy gets a first class is 0.25 and the probability that a girl first class is 0.21 . find the probability that a student selected at random gets a first class. ( 3 marks )