Dos familias fueron al cine, la familia uno está formada por los padres y tres niños quienes pagaron $310 por las entradas, la familia dos está compuesta por los padres, la abuela y cuatro niños ellos pagaron $440 por las entradas. ¿Cuánto cuesta la entrada al cine de un adulto y de un niño?

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?