Abox contains four 40-w bulbs, five 60-w
bulbs, and six 75-w bulbs. if bulbs are se-
lected one by one in random order, what is
the probability that at least two bulbs must be
selected to obtain one that is rated 75w?

0.99483

Step-by-step explanation:

Given : A box contains four 40-W bulbs, five 60-W  bulbs, and six 75-W bulbs.

Total bulbs : 4+5+6=15

The probability of selecting a 75-W bulb :

Using the binomial probability :-

, where P(x) is the probability of getting success in x trials , p is the probability of getting success in each trial and n is the total number of trials.

We have,

The  probability that at least two bulbs must be  selected to obtain one that is rated 75W :-

Hence, the required probability = 0.99483

you didn't give me the choices, so i will just give you the graph so you can look at your choices and choose the right one.