Tickets to a play are priced as follows: Adult tickets: $12. Child tickets: $6. cheryl rings the booking office to buy 6 adult and 3 child tickets . she is told that a 10% booking fee will be added to the ticket price . 2% will then be added if she is paying by credit card . workout the total charge that cheryl will pay if she uses her credit card to buy the ticket?

Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?