Answer:
0.0025 = 0.25% probability that both are defective
Step-by-step explanation:
For each item, there are only two possible outcomes. Either they are defective, or they are not. Items are independent of each other. So we use the binomial probability distribution 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.
5 percent of these are defective.
This means that 
If two items are randomly selected as they come off the production line, what is the probability that both are defective
This is P(X = 2) when n = 2. So


0.0025 = 0.25% probability that both are defective
Hi there!
To find this you can simply use a calculator. All you have to do is divide the numerator by the denominator to see what you get.
7/200 in decimal form is 0.035. Pretty simple.
This fraction cannot be simplified.
Hope this helps!
Answer:
See Explanation
Step-by-step explanation:
The question is incomplete, as the histogram is not attached.
However, the solution to your question is to select the interval with the highest frequency
Take for instance, after getting readings from the histogram, yiu have:
1 - 10: 8
11 - 20: 5
21 - 30: 11
31 - 40: 2
And so on.......
Interval 11 - 20 will represent the required interval because it has the highest frequency.