Question

A homeowner has two smoke detector alarms installed, one in the dining room (adjacent to the kitchen) and one in an upstairs bedroom (above the kitchen). If cooking produces smoke in the kitchen, the probability of setting off the dining room alarm (D) is .95. The probability of setting off the bedroom alarm (B) is .40. The two alarms detect smoke independently of each other. If there is smoke in the kitchen, what is the probability that the smoke will be detected and will set off an alarm

Answer 1

Answer:

0.97

Step-by-step explanation:

Given that a homeowner has two smoke detector alarms installed, one in the dining room (adjacent to the kitchen) and one in an upstairs bedroom (above the kitchen). If cooking produces smoke in the kitchen, the probability of setting off the dining room alarm (D) is .95. The probability of setting off the bedroom alarm (B) is .40.

Both alarms are independent of each other.

Probability for smoke detection=P(any one alarm rings)

=P(Kitchen alarm sets off)+P(bed room alarm sets off)-P(Both sets off)

Since both are independent

P(Both) = $0.95*0.40\\=0.38$

Probability for smoke detection

= 0.95+0.40-0.38

=0.97