Answer/Step-by-step Explanation:
Given:
a = no. of DVDs
b = no. of CDs
Total cost ($) for DVDs and CDs = 
a. The cost for 1 DVD = 2.5(a) = 2.5(1) = $2.5
The cost for 1 CD = 2(b) = 2(1) = $2
b. Total cost for 4 DVDs and 4 CDs:
Substitute a = 4, and b = 4 into the equation.
Total cost for 4 DVDs and 4 CDs = $18
c. To find out if $20 would be enough to buy 6 DVDs and 3 CDs, substitute a = 6, and b = 3 into the equation. Solve for the total cost to see if it equals $20 or is less than $20. If it's greater than $20, then it won't be enough.
6 DVDs and 3 CDs cost more than $20, therefore, $20 is not enough.
A straight angle is 180 degrees in a right angle is 90 degrees
Answer:
The expected number of sales of this store from this sample of 30 is 6.
Step-by-step explanation:
For each prospect, there are only two possible outcomes. Either there is a trade, or there is not. Prospects are independent of each other. So we use the binomial probability distribution 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:
A retail variety store that advertises extensively by mail circulars expects a sale with 20% probability.
This means that 
Suppose 30 prospects are randomly selected from a city-wide mailing.
This means that 
What is the expected number (mean) of sales of this store from this sample of 30?
The expected number of sales of this store from this sample of 30 is 6.
You add the whole numbers together first and then you do the numerators then the denominators. Like for example, #2 would be 2 and then 4 on the top and 6 on the bottom since they share a common denominator! Hoped this helps.
Answer: c = 3
Step-by-step explanation: Distribute 0.2 to (10-5c)
2-1c=5c-16
Then subtract 2 on both sides and subtract the 5c.
-1c=5c-18
-6c=-18
Then divide -6 to -18
-18/-6 = 3
