Abox contains 20 lightbulbs, of which 5 are defective. if 4 lightbulbs are picked from the box randomly, the probability that at most 2 of them are defective is . nextreset

The probability that at most 2 of them are defective is 0.9492 or 94.92%

Step-by-step explanation:

A box contains 20 light bulbs, out of which 5 are defective.

So the probability of selecting a defective bulb is

Now we have to pick 4 lightbulbs the box randomly, so that at most 2 of them are defective.

As we can have only two possibilities i.e either defective or not defective, so we can treat this as Binomial distribution.

In Binomial distribution,

where,

p = probability of success

n = number of trials

At most 2 defective means, either 0 defective or 1 defective or 2 defective bulbs. So the probability that at most 2 defectives from a random draw of 4 bulbs is,

sin3a=12/15

step-by-step explanation:

since one side was multiplied by 3 the other side must also be multiplied by 3.