Question

If a bateria culture starts with 4000 bateria and doubles every 30 minutes, how many minutes will it take the population to reach 42000?

Answer 1

\[4000\times 2^{\frac{t}{30}}=42000\] solve for t

Answer 2

can you finish from here?

Answer 3

um sorta no.... I really suck at exponets... Im so dead for the final Friday
How do I do it

Answer 4

Don't tell me!
Just tell me how to solve. No answering

Answer 5

start by dividing by 4000

Answer 6

then you can solve for
\[\frac{t}{30}\] in one step if you recall to solve
\[b^x=A\] for x you write
\[x=\frac{\ln(A)}{\ln(b)}\]

Answer 7

10.5= 2^(t/30)

Answer 8

ok then one more step to get
\[\frac{t}{30}\]

Answer 9

divide by 2 on both sides?

Answer 10

no, now you have to use logarithms

Answer 11

oh... this is where i mess up T.T um ok 1n(10.5)/1n (2) =t/30

Answer 12

yes!

Answer 13

so
\[t=\frac{30\ln(10.5)}{\ln(2)}\] and now a calculator. will get the answer in minutes
i mean the answer will have minutes for the units

Answer 14

i got 3.3923174 = t/30 so multiply 30 on both sides and I got 101.769

Answer 15

Omg thanks so mcuh! I def. Love this site I hope I can help out too just like you helped me <3

Answer 16

that is what i get too
http://www.wolframalpha.com/input/?i=30ln%2810.5%29%2Fln%282%29

Answer 17

yw

Answer 18

XD that site ive been trying to avoid using...

Answer 19

well i just use it as a calculator. we can do your last problem too if you like. i think it is easier than you think

Answer 20

Oh? Ok!
Which was that I forgot already