Answer:
300
Step-by-step explanation:
In any 4-sided shape, the angles add to 360. if angles 1 & 2 are 180, 3 & 4 are also 180. the answer is D
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
The sum exterior angles of a square are:
4*90=360°