Answer:
5/9
Step-by-step explanation:
Let the denominator be x and numerator be y.
Given, numerator is 4 less than denominator
=> y = x - 4 ...(1)
When 5 is added to both:
Numerator = y + 5 , and, denominator = x + 5
Now their ratio is 5/7.
=> (y + 5)/(x + 5) = 5/7
=> 7(y + 5) = 5(x + 5)
=> 7y + 35 = 5x + 25
=> 7y - 5x = 25 - 35
=> 7(x - 4) - 5x = -10 {y=x-4}
=> 7x - 28 - 5x = -10
=> 2x = 18
=> x = 9
Thus,
Fraction is y/x = (x-4)/x = (9-4)/9 = 5/9
Answer:D
Step-by-step explanation: the average of the 30 stocks in the Dow Jones increased
Answer:
The person in the at-risk population is much more likely to actually have the disease
Step-by-step explanation:
The probability of a randomly selected doctor having the disease is 1 in 1,000 (P(I)=0.0001).
The probability that a doctor is infected with SARS, given that they tested positive is:

The probability of a randomly selected person from the at-risk population having the disease is 20 in 100 (P(I)=0.20).
The probability that a person in the at-risk population is infected with SARS, given that they tested positive is:

Therefore, the person in the at-risk population is much more likely to actually have the disease
Answer:
a) 0.1587
b) 0.023
c) 0.341
d) 0.818
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 515
Standard Deviation, σ = 100
We are given that the distribution of SAT score is a bell shaped distribution that is a normal distribution.
Formula:
a) P(score greater than 615)
P(x > 615)
Calculation the value from standard normal z table, we have,

b) b) P(score greater than 715)
Calculating the value from the standard normal table we have,

c) P(score between 415 and 515)

d) P(score between 315 and 615)
