Compré 18 cuadernos, 24 carpetas y 17 lapiceras. El precio de las carpetas excede al de los cuadernos en un 40%, mientras que el precio de las lapiceras es el 20% del precio de los cuadernos. Si el importe de la compra fue de $11.825, calcular el precio unitario de cada artículo

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?