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2 years ago

What is the doubling time of bacteria if you start with two bacteria and there are 128 bacteria after 3hrs?

Mathematics

1 answer:

iogann1982 [59]2 years ago

5 0

Answer:

B) 30min

Step-by-step explanation:

Start with 2 and continue to multiply that by 2 until you get 128

2 x 2 = 4

4 x 2 = 8

8 x 2 = 16

16 x 2 = 32

32 x 2 = 64

64 x 2 = 128

Then start with what you think could be the right answer based on how many intervals there are.

You know it can't be 15 because there definitely isn't enough and you know its not 1hr because theres way more than 3.

So you're left with either B) 30min or C) 45min

It has to be B) 30min because there are 6 intervals and 30min goes into an hour twice, meaning that if every 2 intervals is an hour there are 3 hours.

You might be interested in

15) In your own words, write three or four sentences explaining what exponents are and how they are used in math

Scorpion4ik [409]

Answer:

Exponents

Step-by-step explanation:

exponents are basic short cut to write numbers like 100, 1000, 10000, 1000000 and so on.

Exponents can also be defined as 10 raised to a power x whether positive or negative

$10 {}^{x}$

They are mostly used in expressing units in standard form.

<h3>examples of basic positive exponents</h3>

${10}^{2} = 100$

$10 {}^{3} = 1000$

${10}^{4} = 10000$

${10}^{5} = 100000$

basically the power represent the the number of zeroes after the 1.

<h3>examples of basic negative exponents</h3>

${10}^{ - 2} = 0.01$

${10}^{ - 3} = 0.001$

${10}^{ - 4} = 0.0001$

$10 ^{ - 5} = 0.00001$

in negative exponents the power represents the number of zeroes before the 1. including the 0 behind the decimal point.

this is the basic lay down of how exponent work but one more quick example for maximum understanding

<h3>quick example</h3>

$4 \times {10}^{4} = 0.0004$

$4 \times {10}^{4} = 40000$

$8.69 \times 10 {}^{ - 3} = 0.00869$

$8.69 \times 10 {}^{ 3} = 8690$

hope you grasp the concept involved in multiplication with other terms.

cheers

6 0

2 years ago

Let A be a set of numbers.

LUCKY_DIMON [66]

Answer:

a. closed under addition and multiplication

b. not closed under addition but closed under multiplication.

c. not closed under addition and multiplication

d. closed under addition and multiplication

e. not closed under addition but closed under multiplication

Step-by-step explanation:

Let A be a set of all integers divisible by 5.

Let $x,y$ ∈A such that $x=5m\,,\,y=5n$

Find $x+y,xy$

$x+y=5m+5n=5(m+n)$

So, $x+y$ is divisible by 5.

$xy=(5m)(5n)=25mn=5(5mn)$

So,

$xy$ is divisible by 5.

Therefore, A is closed under addition and multiplication.

Let A = { 2n +1 | n ∈ Z}

Let $x,y$ ∈A such that $x=2m+1\,,\,y=2n+1$ where m, n ∈ Z.

Find $x+y,xy$

$x+y=2m+1+2n+1=2m+2n+2=2(m+n+1)$

So,

$x+y$ ∉ A

$xy=(2m+1)(2n+1)=4mn+2m+2n+1=2(2mn+m+n)+1$

So,

$xy$ ∈ A

Therefore, A is not closed under addition but A is closed under multiplication.

$Let A=\{2,5,8,11,14,...\}$

Let $x=2,y=5$ but $x+y=2+5=7$ ∉A

Also,

$xy=2(5)=10$ ∉A

Therefore, A is not closed under addition and multiplication.

Let A = { 17n: n∈Z}

Let $x,y$ ∈ A such that $x=17n,y=17m$

Find x + y and xy

$x+y=17n+17m=17(n+m)$

$xy=(17m)(17n)=289mn=17(17mn)$

So,

$x+y,xy$ ∈ A

Therefore, A is closed under addition and multiplication.

Let A be the set of nonzero real numbers.

Let $x,y$ ∈ A such that $x=-1,y=1$

Find x + y

$x+y=-1+1=0$

So,

$x+y$ ∈ A

Also, if x and y are two nonzero real numbers then xy is also a non-zero real number.

Therefore, A is not closed under addition but A is closed under multiplication.

4 0

2 years ago

The triathletes were offered water as they rode by the volunteer station. The volunteers handed them cones with the dimensions s

Zolol [24]

Find the area of the cone:
Area of cone: ⅓r^2h
⅓r^2h
= ⅓(3.5)^2(7)
= ⅓(12.25)(7)
= 1/3(85.75)
= 85.75/3
1/3 cup sloshed out:
(85.75/3 )/3
= 29.9 cubic cm

7 0

1 year ago

Hello does anyone know how to solve this?

Radda [10]

Hello from MrBillDoesMath!

Answer: 2 ^ -4 ( = 1/16)

Discussion:

- 4 log {8} 2 {8} is used instead of subscript notation

Basic property of logarithms is that exponents become multipliers and vice versa:

-4 log {8} 2 = log {8} (2^ -4)

Thank you,

MrB

5 0

2 years ago

Can u plsss help if you d tysm!!

stich3 [128]

2,2,and2 because there are 2 sides of a coin, 2 cards, and 2 marbles

8 0

2 years ago