A certain movie theater hass 400 seats arranged in 40 rows e

A certain movie theater hass 400 seats arranged in 40 rows (each row has 10 seats arranged from left to right) Each seat is occupied by a visitor with probability 1/4 independently of all other seats. A visitor will be comfortable if there is a seat both to the left and to the right (he/she is not seated at the edge of a row) and both of these seats are unoccupied. If N is the nuber of comfortable visitors compute hte expectation and the variance of N.

Solution