How do I do this problem properly?

At a lunchron, guests are offered a selection of five different grilled vegetables and four different meats. in how many waya could one choose three vegetables and two meats?

If sin(x) = 0 and cos(x) = 1, what is tan(x)?

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?