Among the 16 bulbs, 3 are non-standard. Find the probability that two bulbs taken at the same time turn out to be non-standard
August 3, 2020 | Education
| Let’s designate events:
A – “the first bulb will be non-standard”;
B – “the second bulb will be non-standard”.
Events A and B are dependent.
The probability that the first bulb is non-standard:
P = 3/16
The probability of the second light bulb being non-standard, provided that the first light bulb turned out to be non-standard, is
P = 2/15
It is taken into account that the total number of bulbs and the number of non-standard among them will decrease by one if the first light bulb is non-standard. According to the theorem of multiplication of probabilities for two dependent events
P = 3/16 * 2 * 15 = 1/40 = 0.025
