Nanette must pass through three doors as she walks from her company's foyer to her office. Each of these doors may be locked or unlocked. Let B be the event that exactly two doors are locked. List the outcomes of B . [Let "L" designate "locked" and "U" designate "unlocked".]
A) {LLU, LUL, ULL}}
B) {LLL, LLU, LUL, LUU, ULL, ULU, UUL, UUU}
C) {LLU, LUL, ULL, LUU, ULU, UUL}
D) None of these.

Question

Quizplus · Accepted Answer

The event B specifies that exactly two doors are locked. The outcomes that match this description are LLU (first two doors locked, last one unlocked), LUL (first and last doors locked, middle one unlocked), and ULL (last two doors locked, first one unlocked). These are the only combinations where exactly two doors are locked and one is unlocked.

Nanette Must Pass Through Three Doors as She Walks from Her