Answer:
a) P(4) = 0.1168
b) P(More than 2) = 0.3993
Step-by-step explanation:
For each question, there are only to possible outcomes. Either the students guesses the correct answer, or he guesses the wrong. Each question is independent of other questions. 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.
9 questions.
This means that 
Each question has four choices.
This means that 
(a) Find P(4).
This is P(X = 4).
So
P(4) = 0.1168
(b) Find P (More than 2).
Either the student answers 2 or less questions correctly, or the student answers more than 2 correctly. The sum of the probabilities of these events is 1. Then
We want 
. Then
In which
So
Then
P(More than 2) = 0.3993
Notice -y in the first equation and y in the second equation. If you add -y to y, you get zero, and the y variable is eliminated. We add the equations to use the elimination method and eliminate y.
3x - y = 1
-2x + y = 2
Add equations to get
x = 3
Now that we have x = 3, we substitute 3 for x in the first equation and solve for y.
3(3) - y = 1
9 - y = 1
-y = -8
y = 8
Solution: x = 3; y = 8
if 1 inch is added, you would add 2 inches to to each side of rectangle.
You would have: W+2, and, L+2,
Now let W+2 = x and, L+2 = y
Total area = x*y=M
If 1 inch is added again, like above you add 2 inches to both sides, you would then have:
(x+2)(y+2)=M+52;
xy+2x+2y+4=M+52;
xy=M
2x+2y=48
x+y=48/2=24
Now solve :
W+2+ L+2=24
W+L=20
The perimeter is 2(W+L)=20*2 = 40 inches.
Answer:
x=9
Step-by-step explanation:
We have been given the following proportion;
x/6 = 6/4
In order to solve for x, we simply make x the subject on the left hand side;
To do this we multiply both sides by 6,
(x/6)*6 = (6/4)*6
x = 36/4
x = 9
The value of x is thus 9
Answer:
800
Step-by-step explanation:
i dont know how to explain. i just did the math. hope this helps.
it wouldnt be 600 because thats 1/2 of 1200 not 2/3.
