Bacterial Multiplication Numbers - USMLE Forums
 USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
 Home USMLE Articles USMLE News USMLE Polls USMLE Books USMLE Apps
 USMLE Forums Bacterial Multiplication Numbers

 USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam

#1
12-25-2010
 USMLE Forums Scout Steps History: 1 + CK Posts: 71 Threads: 26 Thanked 50 Times in 19 Posts Reputation: 60
Bacterial Multiplication Numbers

Hi All,
Total streptococcus - 2 x 102 in the media, how many bacteria there will be after they double six times?
I know this is not difficult but I absolutely forget how to calculate it So little bit explain it not only simple answer.

#2
12-25-2010
 USMLE Forums Scout Steps History: 1+CK+CS Posts: 99 Threads: 12 Thanked 63 Times in 27 Posts Reputation: 73

2*2*2*2*2*2*2=1.28*10 4
#3
12-25-2010
 USMLE Forums Scout Steps History: 1 + CK Posts: 71 Threads: 26 Thanked 50 Times in 19 Posts Reputation: 60

Quote:
 Originally Posted by kundra 2*2*2*2*2*2*2=1.28*10 4
Thank you for such detailed description
Are you kidding?
My question is - technique multiplying, so why 1.28?

#4
12-25-2010
 USMLE Forums Master Steps History: 1+CK+CS Posts: 590 Threads: 31 Thanked 1,270 Times in 416 Posts Reputation: 1294

Quote:
 Originally Posted by deyneko Thank you for such detailed description Are you kidding? My question is - technique multiplying, so why 1.28?
kundra took:
200 doubled six times, so
400, 800, 1600, 3200, 6400, 12800
12800 can also be written as 1.28 x 10^4

kundra did it the faster way:
2x10^2 doubled six times is (2x10^2) x (2^6)
which also comes out to 1.28 x 10^4
#5
12-25-2010
 USMLE Forums Guru Steps History: 1 + CK Posts: 373 Threads: 30 Thanked 409 Times in 179 Posts Reputation: 419

Quote:
 Originally Posted by deyneko Thank you for such detailed description Are you kidding? My question is - technique multiplying, so why 1.28?
The technique is simple......

initial cell count = 2 x 10^2= 200
So in order to double it multiply it by 2.

2 x 2 x 10^2= 2 x200= 400

You want to double it six times, multiple it by 2 six times..

2 x 2 x 2 x 2 x 2 x 2 x 2 x 10 ^2 =128x 10^ 2= 1.28 x 10^4
__________________
Knowing is not enough; we must apply.
Willing is not enough; we must do.
 The above post was thanked by: deyneko (12-25-2010)

 Tags Microbiology-, Step-1-Questions

Message:
Options

## Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
User Name:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
 AMG IMG ---
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

 Not yet Step 1 Only CK Only CS Only 1 + CK 1 + CS 1+CK+CS CK+CS 1+CK+CS+3 ---
Favorite USMLE Books
 What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
 Where you live. Leave blank if you don't want to tell.

## Log-in

 Similar Threads Thread Thread Starter Forum Replies Last Post achistikbenny USMLE Step 1 Forum 7 09-21-2013 02:47 AM schiwei USMLE Step 1 Forum 1 11-28-2010 05:47 PM dazzles USMLE Step 1 Forum 1 10-07-2010 02:00 AM rasheed USMLE Step 2 CK Bits & Pieces 1 06-12-2010 08:10 PM Estabrak USMLE Step 1 Forum 1 12-03-2009 04:12 PM