Charlotte is working two summer jobs, making $21 per hour tutoring and $14 per hour clearing tables. Last week Charlotte worked twice as many hours tutoring as she worked hours clearing tables hours and earned a total of $168. Graphically solve a system of equations in order to determine the number of hours Charlotte worked tutoring last week, x
,
x, and the number of hours Charlotte worked clearing tables last week,
y
y.

One card is dealt from a 52 card deck. find the probability that the dealt card is a 4 or a black 7

In the diagram of circle a what is m

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?