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3 years ago

Is 67 a prime number?

Mathematics

1 answer:

alexdok [17]3 years ago

7 0

Answer:

yes 67 is a prime number because has only 2 divisors

Step-by-step explanation:

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A 250-gal tank is initially filled with brine (salt-water mixture) containing 100 lb of salt. Brine containing 3 lb of salt per

gulaghasi [49]

Answer:

x(t) = 581.66 lb

Step-by-step explanation:

From the given information:

Consider the salt quantity in the tank at time t be x(t) lb.

∴ the rate of change of salt content in the tank is $\dfrac{dx}{dt}= Rate \ of \ \ inflow - rate \ of \ \ outflow$

where:

the rate of inflow = salt conc. × flow rate = 3 lb/gallon × 7 gallons

=21 lb/s

rate of outflow = salt conc. in the tank × flow rate

= x/250 × 9

= 9x/250 lb/s

∴

$\dfrac{dx}{dt} = 21 - \dfrac{9x}{250}$

$\dfrac{dx}{dt} + \dfrac{9x}{250}= 21$

This is a 1st order linear differentiation,

The integrating factor if $e^{^{ \int \dfrac{9}{250}\ dt}} = e^{^{ \dfrac{9t}{250} }}$

∴

$e^{^{ \dfrac{9t }{250}}} \ \ x(t) = \int 21 e^{\dfrac{9t}{250}} \ dt + C$

$e^{^{ \dfrac{9t }{250}}} \ \ x(t) = 21 \times \dfrac{250}{9}e^{\dfrac{9t}{250}} + C$

$x(t) = \dfrac{1750}{3}+Ce^{^{\dfrac{-9t}{250}}}$ at t = (0) and x(0) = 100 lb

Hence;

$100 = \dfrac{1750}{3}+C$

$C = \dfrac{1750}{3} -100$

$C = - \dfrac{1450}{3}$

∴ $x(t) = \dfrac{1750}{3}-\dfrac{1450}{100}e^{^{\dfrac{-9t}{250}}}$

after time t = 1 minute i.e 60 s

$x(t) = \dfrac{1750}{3}-\dfrac{1450}{100}e^{^{\dfrac{-9 \times 60}{250}}}$

$x(t) = \dfrac{1750}{3}-\dfrac{1450}{100}e^{^{\dfrac{-540}{250}}}$

x(t) = 581.66 lb

5 0

3 years ago

Mr. Martin bought a microwave that was originally priced $225. He received a 30% discount. What is the sale price of the microwa

slamgirl [31]

Answer:

67.50

Step-by-step explanation:

6 0

3 years ago

The sum of two numbers is 13. Two times the first number minus 3 times the second number is one. If your ex stand for the first

Sav [38]

Answer:x = 8, y = 5

Step-by-step explanation:The sum of two numbers is 13. Two times the first number minus three times the second numberis 1. If you let x stand for the first number and y for the second number, the two numbers are: A. x = 8, y = 5

6 0

3 years ago

WHAT IS THE LINE OF BEST FIT FOR THE FOLLOWING DATA (1,3) (2,0) (5,-8) (9, -25) . WRITE YOUR ANSWERS IN THE FORM OF Y= AX+ B

dimulka [17.4K]

Answer:

3.471 + 7.2516 x

Step-by-step explanation:

Given the data:

(1,3) (2,0) (5,-8) (9, -25) .

-8

-25

The line of best fit for the data given can be obtained using an online regression calculator :

The equation of best fit for the data is thus;

Best fit equation; y = -3.471 + 7.2516x

Intercept = - 3.471 ;

Slope = 7.2516

5 0

3 years ago

The relative growth rate for a certain type of bacteria population is 85% per hour. A small culture has formed and in just 2 hou

harkovskaia [24]

Let us assume the initial number of bacteria in the culture = xAfter 1 hour,The number of bacteria = 185x/100 = 1.85xAfter 2 hours,The number of bacteria = (185 * 1.85x)/100 = 3.42xSo3.42x = 12500x = 12500/3.42 = 3654.97 = 3655From the above deduction, we can conclude that the initial number of bacteria in the culture is 3655.

8 0

3 years ago

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