(a) From the histogram, you can see that there are 2 students with scores between 50 and 60; 3 between 60 and 70; 7 between 70 and 80; 9 between 80 and 90; and 1 between 90 and 100. So there are a total of 2 + 3 + 7 + 9 + 1 = 22 students.
(b) This is entirely up to whoever constructed the histogram to begin with... It's ambiguous as to which of the groups contains students with a score of exactly 60 - are they placed in the 50-60 group, or in the 60-70 group?
On the other hand, if a student gets a score of 100, then they would certainly be put in the 90-100 group. So for the sake of consistency, you should probably assume that the groups are assigned as follows:
50 ≤ score ≤ 60 ==> 50-60
60 < score ≤ 70 ==> 60-70
70 < score ≤ 80 ==> 70-80
80 < score ≤ 90 ==> 80-90
90 < score ≤ 100 ==> 90-100
Then a student who scored a 60 should be added to the 50-60 category.
The value of the probability P(A and B) is 0.20
<h3>How to determine the
probability?</h3>
The given parameters about the probability are
P(A or B) = 0.9
P(A) = 0.5
P(B) = 0.6
To calculate the probability P(A and B), we use the following formula
P(A and B) = P(A) + P(B) - P(A or B)
Substitute the known values in the above equation
P(A and B) = 0.5 + 0.6 - 0.9
Evaluate the expression
P(A and B) = 0.2
Hence, the value of the probability P(A and B) is 0.20
Read more about probability at
brainly.com/question/25870256
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Answer: (11x-30)
Step-by-step explanation:
(4x+3)+(7x-33)=(11x-30)
Answer:r=8
Step-by-step explanation:
