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VikaD [51]
3 years ago
7

A bacteria culture starts with 160 bacteria and grows at a rate proportional to its size. After 5 hours there will be 800 bacter

ia.
(a) Express the population after t hours as a function of t. population:_______________ (function of t)
(b) What will be the population after 7 hours? ____________
(c) How long will it take for the population to reach 2790? ______________
Mathematics
1 answer:
Leona [35]3 years ago
7 0

Answer:

Step-by-step explanation:

Let the rate at which the bacteria grow be represented by the exponential equation

P(t) = P0e^kt

P(t) is the population of the bacteria after time t

P0 is the initial population

k is the constant of variation

t is the time

If the initial Population is 160 bacteria's, them the equation becomes;

P(t) = 160e^kt

b) if After 5 hours there will be 800 bacteria, this means

at t = 5 p(t) = 800

Substitute and get k

800 = 160e^5k

800/160 = e^5k

5 = e^5k

Apply ln to both sides

Ln5 = lne^5k

ln5 = 5k

k = ln5/5

k = 0.3219

Next is to calculate the population after 7hrs i.e at t = 7

P(7) = 160e^0.3219(7)

P(7) = 160e^2.2532

P(7) = 160(9.5181)

P(7) = 1522.9

Hence the population after 7houra will be approximately 1523populations

c) To calculate the time it will take the population to reach 2790

When p(t) = 2790, t = ?

2790 = 160e^0.3219t

2790/160 = e^0.3219t

17.4375 = e^0.3219t

ln17.4375 = lne^0.3219t

2.8587 = 0.3219t

t = 2.8587/0.3219

t = 8.88 hrs

Hence it will take approximately 9hrs for the population to reach 2790

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What is the Median for the following set of numbers? ​21 23 76 47 55 135 45 30 17
Leno4ka [110]

Answer:

Median = 45

Step-by-step explanation:

We are given the following data set:

21, 23, 76, 47, 55, 135, 45, 30, 17

Median is the number that divides the data into two equal parts.

Formula:

Median:\\\text{If n is odd, then}\\\\Median = \displaystyle\frac{n+1}{2}th ~term \\\\\text{If n is even, then}\\\\Median = \displaystyle\frac{\frac{n}{2}th~term + (\frac{n}{2}+1)th~term}{2}

Sorted data:

17, 21, 23, 30, 45, 47, 55, 76, 135

Sample size = 9, which is odd

Median =

\dfrac{9+1}{2}^{th}\text{ term} = \dfrac{10}{2}^{th}\text{ term} = 5^{th}\text{ term}\\\\= 45

The median of given set of numbers is 45.

7 0
3 years ago
Please help me find the area of shaded region and step by step​
Bumek [7]

Answer:

Part 1) A=60\ ft^2

Part 2) A=80\ cm^2

Part 3) A=96\ m^2

Part 4) A=144\ cm^2

Part 5) A=9\ m^2

Part 6) A=(49\pi -33)\ in^2

Step-by-step explanation:

Part 1) we know that

The shaded region is equal to the area of the complete rectangle minus the area of the interior rectangle

The area of rectangle is equal to

A=bh

where

b is the base of rectangle

h is the height of rectangle

so

A=(12)(7)-(8)(3)

A=84-24

A=60\ ft^2

Part 2) we know that

The shaded region is equal to the area of the complete rectangle minus the area of the interior square

The area of square is equal to

A=b^2

where

b is the length side of the square

so

A=(12)(8)-(4^2)

A=96-16

A=80\ cm^2

Part 3) we know that

The area of the shaded region is equal to the area of four rectangles plus the area of one square

so

A=4(4)(5)+(4^2)

A=80+16

A=96\ m^2

Part 4) we know that

The shaded region is equal to the area of the complete square minus the area of the interior square

so

A=(15^2)-(9^2)

A=225-81

A=144\ cm^2

Part 5) we know that

The area of the shaded region is equal to the area of triangle minus the area of rectangle

The area of triangle is equal to

A=\frac{1}{2}(b)(h)

where

b is the base of triangle

h is the height of triangle

so

A=\frac{1}{2}(6)(7)-(6)(2)

A=21-12

A=9\ m^2

Part 6) we know that

The area of the shaded region is equal to the area of the circle minus the area of rectangle

The area of the circle is equal to

A=\pi r^{2}

where

r is the radius of the circle

so

A=\pi (7^2)-(3)(11)

A=(49\pi -33)\ in^2

7 0
3 years ago
Mr. Garza's family is attending the local soccer game. He has 30 to spend on food and drinks . The cost of chips is $2 and the c
enyata [817]

Answer:

$6

Step-by-step explanation:

let x and y be the number of chip and pretzel bags respectively  : 4x%2B2y%3 C=20 : if x=1 then 4%281%29%2B2y%3C=20--->{{2y<=16}}}--->y%3C=8  : if x=3 then 4%283%29%2B2y%3C=20--->{{2y<=8}}}--->y%3C=4  : so chips 1 and pretzels 8  : chips 3 and pretzels 4.

4 0
3 years ago
PLEASE HELP :'))
andreev551 [17]

Answer:

D) 54 cm

Step-by-step explanation:

We can use the Centroid Theorem to solve this problem, which states that the centroid of a triangle is \frac{2}{3} of the distance from each of the triangle's vertices to the midpoint of the opposite side.

Therefore, R is \frac{2}{3} of the distance from U to V, since the latter is the midpoint of the side opposite to U. We know this because R belongs to UV, so R must be QS's midpoint due to the fact that by definition, the centroid of a triangle is the intersection of a triangle's three medians (segments which connect a vertex of a triangle to the midpoint of the side opposite to it).

We can then write the following equation:

VR=\frac{1}{3} UV

Substituting VR = 18 into the equation gives us:

18=\frac{1}{3} UV

Solving for UV, we get:

18=\frac{1}{3} UV

3 *18=3*\frac{1}{3}UV (Multiply both sides of the equation by 3 to get rid of UV's coefficient)

54=UV (Simplify)

UV=54 (Symmetric Property of Equality)

Therefore, the answer is D. Hope this helps!

7 0
2 years ago
Lancer watched 6 videos. Each video was 33.5 minutes long. How long did Perla spend watching videos? A.6 minutes B.27.5 minutes
Mumz [18]
201 minutes because 6 multiplied by 33.5 = 201 minutes

5 0
3 years ago
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