If Ann can build the model in 3 hours, then in 1 hour she gets 1/3 of it done. Likewise, if Sam can build the model in 6 hours, then in 1 hour he gets 1/6 of it done. We are looking to find how long it takes when they combine their efforts, so we will add the two together and set it equal to 1/x, x being the number of hours it takes for both of them to get the whole job done. The equation then looks like this: 
. You will have to find the common denominator to add those fractions, and once you do, cross multiply to solve for x.
A) The first one equals to 5
Step by step:
Change all denominators to 28, what you do to the bottom you do to the top.
After adding simplify.
Answer:
a
The probability that the selected joint was judged to be defective by neither of the two inspectors is 
b
The probability that the selected joint was judged to be defective by inspector B but not by inspector A is 
Step-by-step explanation:
From the question we are told that
The sample size is 
The number of outcome for inspector A is 
The number of outcome for inspector B is 
The number of joints judged defective by both inspector is 
The the probability that the selected joint was judged to be defective by neither of the two inspectors is mathematically represented as
Now
substituting values
So
the probability that the selected joint was judged to be defective by inspector B but not by inspector A is mathematically represented as
Now
substituting values
So
Answer:
Step-by-step explanation:
To find the 5th term in the expansion, we first will need to apply the binomial theorem. I have attached an image of the binomial theorem formula due to not being able to type it.
After applying the binomial theorem and simplifying, you should get:
Our 5th term here is: 
which is equal to
~Hope this helps! Sorry if my answer is confusing at all, it's pretty difficult to explain.~
