please help me

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lousy

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Oct 25, 2005
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i can not anderstand this question at all and dont know how to do this

the population of a certain type of bacterium is found to increase at the rate each minute when grown at a particular culture(i.e. at any time the number of bacteria is 2% more than the number 1 minute previously)

express the number present after 1 minute as

a) a percentage of the original number
b) a decimal fraction of the original number

please can someone help me to solve this am really desperate!
 
a) What is the original amount (100%) plus the new amount (2%)?

b) To convert a percentage to a fraction, convert from from a percentage to a decimal (by moving the decimal point), and then convert the decimal to a fraction (by putting the non-leading-zero part of the decimal over "1" followed by the same number of zeroes as the decimal had had decimal places). Simplify.

For instance:

. . . . .13% = 0.13 = 13/100

. . . . .12.5% = 0.125 = 125/1000 = 1/8

. . . . .5% = 0.05 = 5/100 = 1/20

. . . . .150% = 1.5 = 15/10 = 3/2

Follow this process with your example.

Hope that helps a bit.

Eliz.
 
thank you very much for your help, i followed your example and i got for

a) 102%?????????

b) 102/100=1.02
and as a fraction 1.02 over 100 i dont think that i can simplify that

so was that all??????????????
 
a) Yes.

b) "Simplifying a fraction" means reducing it to smallest terms, not converting it back to a decimal. Just follow the examples given to obtain the required answer.

Eliz.
 
b) 102 over 100= 51 over 50 :D

the exercise continuous and asks:

if the original number is 50 use the answer b to find

c) the number after 1 minute
d)the number after 2 minutes

i dont think am right but i thought if the population is p and the time in minutes t then p(t+1) = (100+2)%*p(t)

so if p=50 then 102%*50(1+1)=10200 for the question c)


HAVE I LOST IT COMPLETELYYYYYYYY???? :shock:
 
Think about it this way.
after 1 minute it is
p'=(1.02)*p
after 1 more minute (2 minutes) it is
p'=(1.02)*{(1.02)*p} =
(1.02)²*p
after 1 more minute (3 minutes) it is
p'=(1.02)*{(1.02)²*p} =
(1.02)³*p
From that you can see that after n minutes it is (1.02)^n*p

PS: Don't forget to change % to decimal.

BTW: It is better to post new problems as a new thread.
 
so the answer for c) is 1.02*50=51

for d) (1.02)^2 *50=52.02

am i right?

thanks for your help i appreciate it :D
 
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