Answer:
28.6, that is, about 29 are expected to be defective
Step-by-step explanation:
For each battery, there are only two possible outcomes. Either it is defective, or it is not. The probability of a battery being defective is independent of other betteries. So the binomial probability distribution is used to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:

The probability that a battery is defective is 1/14.
This means that 
400 batteries.
This means that 
How many are expected to be defective?

28.6, that is, about 29 are expected to be defective
Answer:
440 I believe is the answer
Step-by-step explanation:
307.8 divided by( 7/10), which gets you 439.714285714. But you round up because if you round down, it would not be enough steps :)
Answer:
is the expression which is equivalent to
.
In other words:

Step-by-step explanation:
Given the expression

solving





∴ 
Thus,

Therefore,
is the expression which is equivalent to
.
I think you multiply them both from the area