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2 years ago

Solve the system by substitution. - 2x – 10y = -2 -4y = x

Mathematics

1 answer:

mihalych1998 [28]2 years ago

4 0

Answer:

x = -4 and y = 1

Step-by-step explanation:

hope this helps please like and mark as brainliest

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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

$\frac{dy}{dt}=ky(1-y)\\\frac{dy}{y(1-y)}=kdt\\\int\limits {\frac{dy}{y(1-y)}} \, =\int\limit {kdt}\\\int\limits {\frac{dy}{y}} +\int\limits {\frac{dy}{1-y}} =\int\limit {kdt}\\\\ln(y)-ln(1-y)=kt+c\\ln(\frac{y}{1-y}) =kt+c\\taking \ exponential \ of\ both \ sides\\\frac{y}{1-y} =e^{kt+c}\\\frac{y}{1-y} =e^{kt}e^c\\let\ A=e^c\\\frac{y}{1-y} =Ae^{kt}\\y=(1-y)Ae^{kt}\\y=\frac{Ae^{kt}}{1+Ae^{kt}} \\at \ t=0,y=10\%\\0.1=\frac{Ae^{k*0}}{1+Ae^{k*0}} \\0.1=\frac{A}{1+A} \\A=\frac{1}{9} \\$

$y=\frac{\frac{1}{9} e^{kt}}{1+\frac{1}{9} e^{kt}}\\y=\frac{1}{1+9e^{-kt}}$

At t = 2, y = 40% = 0.4

c) At y = 75% = 0.75

$y=\frac{1}{1+9e^{-0.8959t}}\\0.75=\frac{1}{1+9e^{-0.8959t}}\\t=3.68\ days$

5 0

3 years ago

In 2002, the Centers for Disease Control and Prevention (CDC) reported that 8% of women married for the first time by their 18th

ehidna [41]

Question:

In 2002, the Centers for Disease Control and Prevention (CDC) reported that 8% of women married for the first time by their 18th birthday, 25% married by their 20th birthday, and 76% married by their 30th birthday. Based on these data, what is the probability that in a family with two daughters, the first and second daughter will be married by the following ages? (Enter your answers to four decimal places.) (a) 18 years of age (b) 20 years of age (c) 30 years of age

Answer:

A.) 0.0064

B.) 0.0625

C.) 0.5776

Step-by-step explanation:

Given the following :

Married by 18th birthday = 8% = 0.08

Married by 20th birthday = 25% = 0.25

Married by 30th birthday = 76% = 0.76

In a family with two(2) daughters :

P(First daughter will be married by 18) = 0.08

P(second daughter will be married by 18) = 0.08

P(1st and 2nd married by 18) = (0.08×0.08) = 0.0064

B.)

P(First daughter will be married by 20) = 0.25

P(second daughter will be married by 20) = 0.25

P(1st and 2nd married by 20) = (0.25×0.25) = 0.0625

C.)

P(First daughter will be married by 30) = 0.76

P(second daughter will be married by 30) = 0.76

P(1st and 2nd married by 30) = (0.76×0.76) = 0.5776

6 0

3 years ago

PLEASE HELP ASAP!!

SpyIntel [72]

C. 0 _________________

7 0

2 years ago

Please help me!! this is a quiz and i have 10 minutes!!

Nookie1986 [14]

Answer:

When y = 1/2, the answer would be 0. When y = -4, the answer would be 9. When y = 0, the answer would be 1.

Step-by-step explanation:

3 0

2 years ago

What’s the value of 1 2/3 divided by 1 7/18 In mixed number fraction form someone please help :)

JulsSmile [24]

12/3=4
4 divided by 17/18 equals to 4* 18/17=72/17= 4 4/17
Thus the answer is 4 4/17

4 0

3 years ago