Answer:
a) p=0.2
b) probability of passing is 0.01696
.
c) The expected value of correct questions is 1.2
Step-by-step explanation:
a) Since each question has 5 options, all of them equally likely, and only one correct answer, then the probability of having a correct answer is 1/5 = 0.2.
b) Let X be the number of correct answers. We will model this situation by considering X as a binomial random variable with a success probability of p=0.2 and having n=6 samples. We have the following for k=0,1,2,3,4,5,6
.
Recall that 
In this case, the student passes if X is at least four correct questions, then
c)The expected value of a binomial random variable with parameters n and p is ![E[X] = np](https://tex.z-dn.net/?f=E%5BX%5D%20%3D%20np)
. IN our case, n=6 and p =0.2. Then the expected value of correct answers is 
Answer:
399 minutes a month
Step-by-step explanation:
As I understand the question the answer would, in other words, be how many minutes you can long-distance call with the economy plan for under $30.
The unit ratio is 5 cents per minute, which equates to 20 minutes worth of call time for one dollar (100/5).
The economy plan is $20 cheaper than the deluxe plan. $20 spent on long-distance calling gets you 400 mintues, but the question asks for an integer that would still leave remaining money.
Therefore the answer is 399 minutes of long-distance calling, which would leave five unspent cents.
Graph each side of the equation and the solution is what the x-value is at the point of intersection. In this case is about -1.25.
:)))
Answer: $120
Step-by-step explanation: 30% off of 120 is 84
