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astraxan [27]
3 years ago
15

Researchers recorded that a certain bacteria population declined from 110,000 to 400 in 30 hours. At this rate of decay, how man

y bacteria will there be in 19 hours? Round to the nearest whole number.
Mathematics
1 answer:
Arlecino [84]3 years ago
6 0

Answer:

  3137

Step-by-step explanation:

The decay factor is 400/110,000 = 1/275 in 30 hours. Assuming an exponential decay, the equation for the number remaining can be ...

  n(t) = 110,000·(1/275)^(t/30)

Then after 19 hours, the number remaining is ...

  n(19) = 110,000·(1/275)^(19/30) ≈ 3137

There will be about 3137 bacteria after 19 hours.

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0.15(y-0.2)=2-0.5(1-y)<br><br> The answer is -153/35 I just need to know how to get that
butalik [34]

Answer:

y=-\dfrac{153}{35}.

Step-by-step explanation:

The given equation is

0.15(y-0.2)=2-0.5(1-y)

Using distributive property, we get

0.15(y)+0.15(-0.2)=2-0.5(1)-0.5(-y)

0.15y-0.03=2-0.5+0.5y

0.15y-0.03=1.5+0.5y

Isolate variable terms.

0.15y-0.5y=1.5+0.03

-0.35y=1.53

Divide both sides by -0.35.

y=\dfrac{1.53}{-0.35}

y=-\dfrac{1.53}{0.35}\times \dfrac{100}{100}

y=-\dfrac{153}{35}

Therefore, y=-\dfrac{153}{35}.

6 0
3 years ago
Find an equation for the plane tangent to the surface given by z = x^2 + y^4 + e^xy
aivan3 [116]

Answer:

z = 2x + y - 2

Step-by-step explanation:

To find an equation for a plane tangent to a surface, we need two things:

1) A surface Z = f(x,y)

2) A point P(x0,y0,z0)

The equation for the plane tangent to the surface Z at the point P is given by the equation a)

a) Zx(x0,y0,z0)*(x-x0) + Zy(x0,y0,z0)*(y-y0) -(z-z0) = 0

Where Zx is the partial derivative of Z in relation to x and Zy is the partial derivative of Z in relation to y

In your problem, we have that Z = x^2 + y^4 + e^(xy)

So Zx(x,y,z) = 2x + ye^(xy)

We have that (x0,y0,z0) = (1,0,2), so Zx(1,0,2) = 2

Zy(x,y,z) = 4y^3 + xe^(xy)

Zy(1,0,2) = 1

According to equation a), we have

Zx(1,0,2)*(x-2) + Zy(1,0,2)*(y-0) -(z-2) = 0

2*(x-2) + y - z + 2 = 0

z = 2x + y - 2 is the equation for the plane tangent to this surface at this point.

7 0
4 years ago
A math test is worth 100 points and has 38 problems. Each problem is worth either 5 points or 2 points. How many problems of eac
Nat2105 [25]

Answer:

<em><u>5</u></em><em><u> </u></em><em><u>points</u></em><em><u> </u></em><em><u>question</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>8</u></em>

<em><u>and</u></em><em><u> </u></em><em><u>2</u></em><em><u> </u></em><em><u>po</u></em><em><u>ints</u></em><em><u> questions</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>3</u></em><em><u>0</u></em><em><u> </u></em><em><u>!</u></em><em><u>!</u></em>

Step-by-step explanation:

Let the number of 5 points questions be x and number of the 2 points questions be y !!

Given :- The paper has 38 problems

i.e,

number of 5 points Q + number of 2point Q = 38

=> x + y = 38

=> x = 38 - y .... ( i )

And , The test worth 100 pts :-

There must be x number of Questions which carry 5 points and there must y number of questions which carries 2 points ( as assume above )

so, 5x + 2y = 100 .... ( ii )

Putting value of the x in ( ii )

5 ( 38 - y ) + 2y = 100

190 - 5y + 2y = 100

- 3y = - 90

y = 30

Putting value of y in ( i )

x = 38 - y

x = 38 - 30

x = 8

So, the Number of 5points Question is

x = 8

and , the number of 2 points questions is y = 30 !!

4 0
4 years ago
9. Speedy Boat Rental charges a $15 deposit fee plus $2 for each hour of use to rent a paddle boat. Write an equation to find ou
rodikova [14]

Answer:

9 hours

Step-by-step explanation:

3 0
4 years ago
Each step in a procedure to solve this equation is shown. Find where the first error occurs. Given: 2(x - 4) = 8x + 16
quester [9]

Answer:

b

Step-by-step explanation:

It is B because he makes the error of adding 8x to 2x instead of subtracting 8x from 2x.

3 0
3 years ago
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