The copy machine in an office is very unreliable.If it was working yesterday, there is an 80% chance it will work today.If it was not working yesterday, there is a 10% chance it will work today.If it is working today, what is the probability that it will be working 2 days from now?
A)0.16
B)0.64
C)0.66
D)0.80

Question

Quizplus · Accepted Answer

To find the probability that the machine will be working 2 days from now, given that it is working today, we calculate the probability of it working each day. If it works today, the probability it works tomorrow is 0.8. If it works tomorrow, the probability it works the day after is also 0.8. Therefore, the probability it works 2 days from now is 0.8 * 0.8 = 0.64. However, we must also consider the scenario where it doesn't work tomorrow but works the day after, which is 0.2 * 0.1 = 0.02. Adding these probabilities gives 0.64 + 0.02 = 0.66.

The Copy Machine in an Office Is Very Unreliable