For Mr.Greene's wireless phone bill, 3 months costs $180. For 9 months, his Bill was $540. Which equation best represents the re
2 answers:
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Answer:
Pies=$0.85
Donuts= $1.20
Step-by-step explanation:
In the equation let p stand for the number of pies and d stand for the number of donuts.
To solve this set up 2 equations, one representing bill and the other representing Mary Ann.
- Bill's equation is 5p+7d=$12.65.
- Mary Ann's equation is 6p+6d=$12.30
Then solve using a system of equations. Systems of equations can be solved using elimination or substitution. I will use substitution. Solve bill's equation for p. This gives you . Then, you can substitute that into Mary Ann's equation. This looks like
. Solve for d. Once you solve d=1.20. Finally, substitute 1.20 back into either Bill's or Mary Ann's for d and solve for p. No matter which equation you use p=0.85.
Answer:
The probability is 0.0775
The expected value is 4.75 clubs
The standard deviation is 1.8875 clubs
Step-by-step explanation:
The variable X follows a binomial distribution, because we have n identical and independent events (19 cards) with a probability p of success and 1-p of fail (there is a probability of 1/4 to be club and 3/4 to be diamond, heart or spade). Then, the probability that x of the n cards are club is:
So, the probability P of drawing at least 8 clubs is:
P = P(8) + P(9) + P(10) + ... + P(18) + P(19)
Replacing, the values of x, from 8 to 19, on the equation above, we get:
P = 0.0775
Additionally, the expected value E(x) and standard deviationS(x) for this distribution is given by:
E(x)=np = 19(0.25) = 4.75