Add. -85.53+(-41.00) A. -126.53 B. -44.47 C. 44.53 D. 126.47

LekaFEV [45]

Do a proportion
65/100= x/80

Cross multiply and divide
80 x 65= 5, 200
5, 200 divided by 100 is 52
52 members left
80-52= 28
Answer is 28 members

5 0

3 years ago

Find each sum (-4y+3) + (11y-5)

Airida [17]

Answer:

7y−2

Step-by-step explanation:

8 0

3 years ago

Suppose 10000 people are given a medical test for a disease. About1% of all people have this condition. The test results have a

Alina [70]

Answer:

The percent of the people who tested positive actually have the disease is 38.64%.

Step-by-step explanation:

Denote the events as follows:

X = a person has the disease

P = the test result is positive

N = the test result is negative

Given:

$P(X)=0.01\\P(P|X^{c})=0.15\\P(N|X)=0.10$

Compute the value of P (P|X) as follows:

$P(P|X)=1-P(P|X^{c})=1-0.15=0.85$

Compute the probability of a positive test result as follows:

$P(P)=P(P|X)P(X)+P(P|X^{c})P(X^{c})\\=(0.85\times0.10)+(0.15\times0.90)\\=0.22$

Compute the probability of a person having the disease given that he/she was tested positive as follows:

$P(X|P)=\frac{P(P|X)P(X)}{P(P)}=\frac{0.85\times0.10}{0.22} =0.3864$

The percentage of people having the disease given that he/she was tested positive is, 0.3864 × 100 = 38.64%.

3 0

3 years ago

A kayaker spends a morning paddling on a river. She travels 9 miles upstream and 9 miles downstream in a total of 6 hours. In st

tresset_1 [31]

To answer this item, we have 4 as the speed of the kayaker in still water and the speed of current be y.

When the karayaker moves upstream or against the current, his speed would be 4 - y. Further, if he moves downstream or with the current, the total speed would be 4 + y. The time utilized for the travel is equal to the ratio of the distance and the speed.

Total time = 9/(4 - y) + 9/(4 + y) = 6

We multiply the equation by (4-y)(4+y)
9(4-y) + 9(4 + y) = 6(4-y)(4+y)

Simplifying,
72 = 96 - 6y²
Transposing all the constants to only one side of the equation and rearranging,
6y² = 96 - 72
y² = 4
y = 2

Hence, the speed of the river's current is 2 miles/hr. The answer is letter B.) 2 miles/hour.

5 0

3 years ago

What is the domain of F(x) = In(x)?

jekas [21]

Answer as an inequality: $x > 0$

Answer in interval notation: $(0, \infty)$

Answer in words: Set of positive real numbers

All three represent the same idea, but in different forms.

======================================================

Explanation:

Any log is the inverse of an exponential equation. Consider a general base b such that f(x) = b^x. The inverse of this is $f^{-1}(x) = \log_b(x)$

For the exponential b^x, we cannot have b^x = 0. We can get closer to it, but we can't actually get there. The horizontal asymptote is y = 0.

Because of this, $\log_b(x)$ has a vertical asymptote x = 0 (recall that x and y swap, so the asymptotes swap as well). This means we can get closer and closer to x = 0 from the positive side, but never reach x = 0 itself.

The domain of $\log_b(x)$ is x > 0 which in interval notation would be $(0, \infty)$ . This is the interval from 0 to infinity, excluding both endpoints.

------------------------

The natural log function Ln(x) is a special type of log function where the base is b = e = 2.718 approximately.

So,

$\log_e(x) = \text{Ln}(x)$

allowing all of what was discussed in the previous section to apply to this Ln(x) function as well.

------------------------

In short, the domain is the set of positive real numbers. We can't have x be 0 or negative.

8 0

3 years ago