Twenty percent of all telephones of a certain type are submitted for service while under warranty. Of these, 60% can be repaired, whereas the other 40% must be replaced with new units. If a company purchases ten of these telephones, what is the probability that exactly four will end up being replaced under warranty

0.0052 = 0.52% probability that exactly four will end up being replaced under warranty.

Step-by-step explanation:

For each telephone, there are only two possible outcomes. Either they are replaced under warranty, or they are not. The probability of a telephone being replaced under warranty is independent of any other telephone, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.

Twenty percent of all telephones of a certain type are submitted for service while under warranty. Of those, 40% are replaced.

This means that

Company purchases ten of these telephones.

This means that

What is the probability that exactly four will end up being replaced under warranty?

This is P(X = 4). So

0.0052 = 0.52% probability that exactly four will end up being replaced under warranty.

there are 70 more legs than eyes at the dog show (196 – 126 = 70). dogs have two more legs than eyes, and humans have the same number of legs as eyes. thus 70 is twice the number of dogs at the show, so the number of dogs is half of 70, which is 35. to get the number of humans, subtract 35 from 63: 63 – 35 = 28.

step-by-step explanation: