1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Ulleksa [173]
3 years ago
9

A bacteria culture initially contains 100 cells and grows at a rate proportional to its size. After an hour the population has i

ncreased to 230. (a) Find an expression for the number of bacteria after t hours. (b) Find the number of bacteria after 2 hours. (Round your answer to the nearest whole number.) P(2) = ___bacteria (c) Find the rate of growth after 2 hours. (Round your answer to the nearest whole number.) P'(2) = ___bacteria per hour (d) When will the population reach 10,000? (Round your answer to one decimal place.) t = ___hr

Mathematics
1 answer:
goldfiish [28.3K]3 years ago
6 0

Answer:

  • P(t) = 100·2.3^t
  • 529 after 2 hours
  • 441 per hour, rate of growth at 2 hours
  • 5.5 hours to reach 10,000

Step-by-step explanation:

It often works well to write an exponential expression as ...

   value = (initial value)×(growth factor)^(t/(growth period))

(a) Here, the growth factor for the bacteria is given as 230/100 = 2.3 in a period of 1 hour. The initial number is 100, so we can write the pupulation function as ...

  P(t) = 100·2.3^t

__

(b) P(2) = 100·2.3^2 = 529 . . . number after 2 hours

__

(c) P'(t) = ln(2.3)P(t) ≈ 83.2909·2.3^t

  P'(2) = 83.2909·2.3^2 ≈ 441 . . . bacteria per hour

__

(d) We want to find t such that ...

  P(t) = 10000

  100·2.3^t = 10000 . . . substitute for P(t)

  2.3^t = 100 . . . . . . . . divide by 100

  t·log(2.3) = log(100)

  t = 2/log(2.3) ≈ 5.5 . . . hours until the population reaches 10,000

You might be interested in
The profits in hundreds of dollars, P(c), that a company can make from a product is modeled by a function of the price, c, they
Jobisdone [24]
The maximum profit is the y-coordinate of the vertex of the parabola represented by the equation.

P(c)=-20c^2+320c+5120 \\ \\
a=-20 \\
b=320 \\ \\
\hbox{the vertex } (h,k): \\
h=\frac{-b}{2a}=\frac{-320}{2 \times (-20)}=\frac{-320}{-40}=8 \\
k=f(h)=f(8)=-20 \times 8^2+320 \times 8+5120= \\
=-1280+2560+5120=6400

The maximum value is 6400, but the profit is given in hundreds of dollars, so multiply the value by 100.

The maximum profit the company can make is $640,000.
4 0
3 years ago
Read 2 more answers
Use simultaneous equations to solve the following. Three kilograms of jam and two kilograms of butter cost $29 and six kilograms
artcher [175]

Answer:

The cost of 1kg jam is $7 and the cost of 1kg butter is $4

Step-by-step explanation:

Let jam = x

butter = y

3x + 2y = 29 -----(1)

6x + 3y = 54 -----(2)

(1)×2 ->

6x + 4y = 58 -----(3)

(3)-(2) ->

y = 4

suby=4into(2)

6x + 3(4) = 54

6x = 42

x = 7

(Correct me if i am wrong)

6 0
3 years ago
Estimate
Taya2010 [7]
126/10 would mean that from the original number, the decimal point is at 126.0 so when it is divided by 10, it will move over one placement, making it 12.6... I would estimate that your answer is C. 12.6
5 0
3 years ago
Help picture is shown!!!!
daser333 [38]
D,

Symmetry is when you split the shape, but they look the same. 
6 0
3 years ago
Read 2 more answers
What are the restrictions for a? 2a^2+a-15/5a^2+16a+3
koban [17]

ANSWER


The restrictions are

a\ne -3,a\ne -\frac{1}{5}


EXPLANATION


We were given the rational function,


\frac{2a^2+a-15}{5a^2+16a+3}


The function is defined for all values of a, except



5a^2+16a+3=0


This has become a quadratic trinomial, so we need to split the middle term.


We do that by multiplying the coefficient of x^2 which is 5 by the constant term which is 3. This gives us 15.


The factors of 15 that adds up to 16 are 1 and 15.


We use these factors to split the middle term.




5a^2+15a+a+3=0


We now factor to get,


5a(a+3)+1(a+3)=0


We factor further to get,


(a+3)(5a+1)=0



This implies that,


(a+3)=0,(5a+1)=0


This gives


a=-3,a=-\frac{1}{5}


These are the restrictions.





8 0
3 years ago
Other questions:
  • The sum of three consecutive integers is 108. Which equation would be used to solve this word problem? (HINT: The equation has b
    11·2 answers
  • The numbers on this ruler represent centimeters. 170cm
    6·1 answer
  • Helphelphelphe helphelp
    14·1 answer
  • What will be the unit digit of the cube of a number ending with 4 ?
    13·1 answer
  • PLEASE HELP ASAP! What is the value of x in the inequality start fraction seven plus two x over five end fraction minus three le
    12·2 answers
  • Help help please is my final please
    5·1 answer
  • I need help please .
    10·1 answer
  • PLEASE HELP ME NOW!!!! DUE VERY SOON! PLEASE I BEG YOU!
    9·1 answer
  • Which of the following statements is true about the quadratic function f(x) = ax2 + bx + c?
    14·1 answer
  • At a graduation dinner there were 47 guests in all. An equal number of guests were seated at each of 7 large​ tables, and 5 ​lat
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!