Answer:
0.069793787 Approximately = 0.07
Step-by-step explanation:
From this question we have total number of keys to be 12,out of these 12, we know that only one key can open the office.
The probability that this 1 key can open the office is 1/12 = 0.083
Going further we have to apply the geometric distribution.
From the question the door opens after the 3rd time. So 2 trials have failed to open this door.
P(X=3) = (1-0.083)²(0.083)
= 0.840889x0.083
= 0.069793787
Approximately
0.07
