Given that in a room there is an amoeba (only one) and it duplicates itself every second and will fill the entire room in 1 hour. When (in seconds) will the amoebas fill up half the room?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
HOW IS THIS POSSIBLE? I AM NOT ABLE TO UNDERSTAND
Log in to reply
It is given that the amoeba makes himself double in 1 second. Given that the amoeba will fill the room in 1 hour, the previous second the room would be half filled and the next second every amoeba will double itself and fill the room.
At 1800 seconds the room would be .25% full then wouldn't it be half full at 1801
This question should be worded differently. According to the statement only one amoeba is doubling.
Can amoeba fill the remaining half in just a second, that is half the room and also why is amoeba referred to as he? :)
I chuckled to the reference of amoeba as "he" :)
Don't think too seriously. it's just a question :)
Because it doubled from half the room to full room
The room will fill in 3600 sec( 1 hour),if it doubles for every second the room filled at 3599 sec is half of the room,at 3598 sec is quarter of the room,at 3597 sec is half if the quarter of the room and so on.......
It's like a tap filling a bottle - each new drop sticks to the other drops and pushes the water level up. Multiplying cells divide locally right next to each other so they're pushing out to fill the room at each division. Imagine that at the last second, the density of the blob doubles (since a second ago before the doubling, the colony would have been 50% as sparse). In reality, cells are dying as well so you'd have to account for cell count with a little more realistic model.
Cause it is an Amheba
Just for fun:
Mass of amoeba ≈ 1 0 − 8 grams Volume of amoeba ≈ 1 0 − 8 grams / water density = 1 0 − 8 cm 3
Volume after 3600 seconds ≈ 1 0 − 8 cm 3 × 2 3 6 0 0
≈ 1 0 9 8 9 × Volume of Universe
Also, some time during the third minute, the amoebae will collapse into a black hole.
Let N(t) be bacteria count at any time 't' According to the question,we have N(t)=2^t. Now when the room is full ,t=3600 & N=2^3600,Where N is the bacteria count when the room is full.Now when the room is half filled, n(t)=N/2 or, 2^t=(2^3600)/2 On solving we get t=3599. It is quite fascinating 2 observe that Half of the remaining bacteria multiplies in just a second. That's the power of exponential increment!!
http://en.wikipedia.org/wiki/Wheat and chessboard_problem
From the information the question gives us, we know that:
Therefore the room would be half full 1 second before 1 hour, which is 3600 seconds, so the room would be full after 3600-1=3599 seconds. :)
Every second the number of amoeba doubles, that is there
is 1 amoeba at the 0th second
2 amoeba at the 1st second
4 amoeba at the 2nd second
and so on.
At the xth second, there are 2^x amoeba
Let's say in 1 hour there are 2^n amoeba
then half of the room would be (2^n)/2 amoeba and
this would be simply the second before an hour.
As amoeba duplicates itself every second, we would have: 1 second = 2 amoebas; 2 seconds = 4 amoebas; 3 seconds = 8 amoebas; so.....we would have 2^n amoebas at n seconds. Within 1 hour = 3600 seconds, we would have the amoeba filled full the room with 2^3600 amoebas, suppose t is the time the amoebas fill up half the room, we would have 2^3600 = 2*2^t. Solving this equation, we would have t = 3599.
The time it would take for the amoeba to fill up the room is 3600 seconds. This is obtained by multiplying 60 seconds by 60 minutes (there are 60 seconds in a minute and 60 minutes in an hour). Knowing that the amoeba self-double each second, we can state that half a room was filled in 3599 seconds, one second less than 3600. (Except if only 1 amoeba had split. It is possible with how the problem is worded. This would mean that it will take double the time, which would be 7199 seconds.)
All amoebas replicate themselves each second. If in 3600 seconds the room was filled, it means that the previous second contained half the amount of amoebas. 3600 - 1 = 3599
Démosle la vuelta al enunciado. 2^3600 amebas llenan una habitación. Si el número de amebas se divide por 2 cada segundo, ¿en qué segundo habrá la mitad de amebas? La respuesta es obvia.
Why? Why not 3600 - 2, 3600 - 3, or others?
Because it become double in one second so the time is needed to fill the half of the room from the beginning is 3599 second . you need to read the problem carefully :)
I've already posted a detailed solution..check it out..!!
Problem Loading...
Note Loading...
Set Loading...
the last second it doubled from a half to full room therefore 3600-1=3599