3/4 x 6/1 A. 9/4B. 2 1/4C. 4 1/2D. 3 3/5
1 answer:
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Answer:
Step-by-step explanation:
Let X be average interest paid monthly by a bank's Visa cardholders
Given that X is N(28, 8)
In the following to find out probability we convert X to z score and use std normal distribution table
Z =
Probability being less than 1 is here equal to the proportion also.
A) P(X>32) = P(Z>0.5)=0.5-0.1915=0.3085
B) P(X>40) = P(Z>1)=0.5-0.3413=0.1687
C) P(X<19) = P(Z<-1.125)=0.5-0.0438=0.4562
D) We have to find 19th percentile here
Z =-0.88
Answer:
Number of calls received in 1st evening = 24
Number of calls received in 2nd evening = 33
Number of calls received in 3rd evening = 72
Step-by-step explanation:
Let
number of calls received in first evening be "x"
number of calls received in 2nd evening be "y"
number of calls received in 3rd evening be "z"
Total, in 3 evenings, we have 129 phone calls, so we can write:
x + y + z = 129
3rd evening, 3 times as first evening. We can write:
z = 3x
2nd evening, 9 MORE THAN FIRST. So we can write:
y = 9 + x
Now we replace 2nd and 3rd equation in 1st equation to get:
x + y + z = 129
x + 9 + x + 3x = 129
Now, first, we solve for x:
Solving for y:
y = 9 + x
y = 9 + 24
y = 33
Solving for z:
z = 3x
z = 3(24)
z = 72
Thus,
Number of calls received in 1st evening = 24
Number of calls received in 2nd evening = 33
Number of calls received in 3rd evening = 72