A room has three lightbulbs. Each one has a 9%
probability of burning out within the month. Write each probability as a percentage.
What is the probability that at the end of the month at least one of the bulbs will be lit?
To find the probability that at least one of the bulbs will be lit at the end of the month, we can calculate the probability that all of them burn out and then subtract that from 1.
The probability of one bulb burning out is 9% or 0.09. Therefore, the probability of one bulb not burning out is 1 - 0.09 = 0.91.
Now, we have three bulbs that each have a probability of 0.91 of not burning out. The probability of all of them burning out is (0.09) * (0.09) * (0.09) = 0.000729.
The probability of at least one bulb being lit at the end of the month is: 1 - 0.000729 = 0.999271 or 99.9271%.