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2 years ago

What is the sum of 3+(−4) = -1

Mathematics

2 answers:

Dmitry [639]2 years ago

8 0

3+-4=-1
3-4=-1
-1=-1

so the answer is:
-1 = -1

kobusy [5.1K]2 years ago

5 0

3 + -4 is equal to 3 - 4 and 3 - 4 is 1

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riadik2000 [5.3K]

Answer:

b) 0.0007

c) 0.4163

d) 0.2375

Step-by-step explanation:

We are given the following:

We treat securities lose value as a success.

P(Security lose value) = 70% = 0.7

Then the securities lose value follows a binomial distribution, where

$P(X=x) = \binom{n}{x}.p^x.(1-p)^{n-x}$

where n is the total number of observations, x is the number of success, p is the probability of success.

Now, we are given n = 20.

a) Assumptions

There are 20 independent trials.
Each trial have two possible outcome: security loose value or security does not lose value.
The probability for success of each trial is same, p = 0.7

b) P(all 20 securities lose value)

We have to evaluate:

$P(x = 20)\\= \binom{20}{0}(0.7)^0(1-0.7)^{20}\\= 0.0007$

0.0007 is the probability that all 20 securities lose value.

c) P(at least 15 of them lose value.)

$P(x \geq 15)\\= P(x=15) + P(x = 16) + P(x=17) + P(x=18) +P(x = 19) +P(x = 20)\\ \binom{20}{15}(0.7)^{15}(1-0.7)^{5} +...+ \binom{20}{20}(0.7)^{20}(1-0.7)^{0} \\=0.4163$

d) P(less than 5 of them gain value.)

P(gain value) = 1 - 0.7 = 0.3

$P(x < 5)\\= P(x=0) + P(x = 1) + P(x=2) + P(x=3) +P(x = 4)\\ \binom{20}{0}(0.3)^{0}(1-0.3)^{20} +...+ \binom{20}{4}(0.3)^{4}(1-0.3)^{16} \\=0.2375$

7 0

3 years ago

Vivian exchanged her Japanese yen for ?56.92 in U.S. dollars. What equation can be used to find the quantity of Japanese yen tha

Lilit [14]

That is 6120.43 yen rounded to the nearest hundredth because if you exchange 56.92 at a rate of 1 yen is equal to 0.0093 you get 6120.43.

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3 years ago

A rumor spreads through a small town. Let y(t) be the fraction of the population that has heard the rumor at time t and assume t

sladkih [1.3K]

Answer:

The answer is shown below

Step-by-step explanation:

Let y(t) be the fraction of the population that has heard the rumor at time t and assume that the rate at which the rumor spreads is proportional to the product of the fraction y of the population that has heard the rumor and the fraction 1−y that has not yet heard the rumor.

$\frac{dy}{dt}\ \alpha\ y(1-y)$

$\frac{dy}{dt}=ky(1-y)$

where k is the constant of proportionality, dy/dt = rate at which the rumor spreads

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