Question

You have a tube containing 10^2 bacteria. You have taken out 10^2 bacteria. How many bacteria are left in the tube ?

A) approximately 10^7
B) approximately 10^6
C)approximately 10^5
D)approximately 10^9

Answer 1

@thomaster

Answer 2

are you sure that's your entire question?

Answer 3

yeah !!! definitely

Answer 4

Well, I'm not too great at bio, but I'm gonna guess it's either B or C. I think @nincompoop is a bio major tho, so maybe he can help when he's on.

Answer 5

but how can you say that option B or C may be correct ??

Answer 6

Well, even considering exponential growth, it doesn't seem reasonable that you would get 1000000000 out of 100 unless you wait for a considerably long time, so there goes D, and same for 10000000 which would be A. Again though, I'm just guessing :p

Answer 7

yeah...this is general mathematics.
So,why doesn't the option A and D may correct ???

Answer 8

@poopsiedoodle

Answer 9

@Abhisar please help me... !!!

Answer 10

You have a tube containing 10^2 bacteria, then you take out 10^2.
It wants to know how many are left after that?
Are you sure that is the exact question? because based on that ...
it would seem like the answer is 10^2 - 10^2 = 0

Answer 11

yeah!!! the first reaction i mean my first answer would be zero(0) but when i read options,there is nothing like ZERO in options. :P

Answer 12

we just apply MATHEMATICS @Miracrown but this is a BIOLOGY QUESTION !!! :)

Answer 13

lolz....anything an happen

Answer 14

Considering it to be biology, it still looks incomplete. There is no mention of time.

Answer 15

???

Answer 16

I completely agree with you, and that is definitely the question?
@mayankdevnani

Answer 17

The exact phrasing of the question I mean

Answer 18

this is the question of KVPY 2008
question no.48

Answer 19

@Abhisar

Answer 20

I agree with all that's been said, but @mayankdevnani just because this is a biology question doesn't mean we are suddenly in a different universe. Frankly seeing the question, I am in kind of disbelief. There is no mention of the kind of bacteria nor how much time has elapsed since. Not all bacteria grow at the same rate.

Answer 21

but can you give a IDEA how to solve this question :-
1) If time is not included
2)if time is included

Answer 22

@Abhisar ^^^^

Answer 23

Yea like I said before no correct answer choice
If there was something before that said something like:
"The bacteria grow at a rate of which allows them to double every hour."
If a tube with 10^2, and you take 10^2 out a day later, how many are left

But based on that question, It seems to me like there is no correct answer choice

Answer 24

but there is no BONUS in question !!

Answer 25

If time is not included, the answer is undoubtedly 10^2 - 10^2 = 0

If there were a time element, then you would first calculate how many bacteria there were from start up to the moment you take some out

Answer 26

\(A = Pe^{kt}\)
We use the above formula to find the growth in a bacterial culture assuming the growth to be exponential.

A=Final number of bacteria
P=initial number
t=time
k=growth constant.

Answer 27

10^2 * e(rt)
and then subtract out 10^2

Answer 28

what about GROWTH CONSTANT ??

Answer 29

If time is not included, you basically are just guessing. As you don't know what kind of bacteria, their rate of growth, their stage of growth, whether they have any special feature associated with the bacteria. And you don't even know how much time has passed. Even if you have time, you are basically still guessing because of all of that. But I would use A = Pe^(kt) if time is all we have.

Answer 30

i mean what is the value of GROWTH CONSTANT ???

Answer 31

It depends on the culture.

Answer 32

oh !!!

Answer 33

Yes, @abhisar - that would be consistent with the what I said before
about how we would approach it if there were a time component.
The amount at time t is equal to the starting amount multiplied by e to the power of the growth rate times time.

Answer 34

but in this question,the answer which is given by KVPY is option B)10^6

Answer 35

oh I just realized from reading other people's responses that A=Pe^(kt) you would still need to know the growth constant. lol sorry about that.

Answer 36

but the problem is in this question there is no mention of time or a growth rate

Answer 37

are they apply any APPROXIMATION METHOD ??

Answer 38

http://www.purplemath.com/modules/expoprob2.htm
somewhat like questions
you all say about

Answer 39

i have a question :-
IS THERE ANY APPROXIMATION METHOD?
i mean consider time=1 s ,k=1 etc.
something like this to reach the CORRECT ANSWER(option B)

Answer 40

@Abhisar @Miracrown @1DEA

Answer 41

Well, unless there is more to the question on another page or something
This is just a mistake, because based on the information they provided us.
The answer is clearly 0... maybe they "meant" something else
which would provide an answer of 10^6

How much is left?
That has to be 0

Answer 42

I could think of one if you would want to see an example

Answer 43

please !!

Answer 44

think fast
FAST AND FURIOUS

Answer 45

honestly, from I know (I studied biochemistry and molecular biology in college). No there is no approx. method for a generic bacteria. There are approximations used to figure out roughly when to check/harvest bacteria, based on the species of bacteria. But other than that I have not heard of such a thing. Has anyone heard of any approx. method?

Answer 46

so @Miracrown @1DEA and @Abhisar
finally,there is no way to reach option B

and we can say simply that QUESTION IS WRONG !

Answer 47

Here's one:
Bacteria grow with a rate constant of 4.6
Initially, there are 10^2
After 2 hours, you remove 10^2
How many are remaining at this point in time right after you take those 10^2 out?

So first, we need to figure out how many bacteria are there before we take any out
Use A=Pe^(rt)
What do you get?

Answer 48

thank you guys for helping me in VERY CRUCIAL TIME !!
@Miracrown @1DEA @Abhisar

Answer 49

lol, yw :)

Answer 50

not a problem :)

Answer 51

You're most welcome