Your friend has $100 when he goes to the fair. He spends $10 to enter and $20 on food. Rides at the fair cost $2 per ride. Which function can be used to determine how much money he has left over after x rides?

A.) f(x) = -2x + 70
B.) f(x) = 2x + 70
C.) f(x) = -2x - 70
D.) f(x) = -30x + 100

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?