Dunno how to write this one, so I used a screenshot.

http://img111.imageshack.us/img111/8039/mathwordux7.jpg

The thing that trips me up is the 0 seconds.

(Punch) <(I hate Word Problems!)

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- Jun 29th 2008, 01:21 PMmankvillWord problem about Chemical Half-Lives
Dunno how to write this one, so I used a screenshot.

http://img111.imageshack.us/img111/8039/mathwordux7.jpg

The thing that trips me up is the 0 seconds.

(Punch) <(I hate Word Problems!) - Jun 29th 2008, 01:26 PMJhevon
- Jun 29th 2008, 01:27 PMmankvill
a = 38?

- Jun 29th 2008, 01:30 PMJhevon
- Jun 29th 2008, 01:41 PMmankvill
- Jun 29th 2008, 01:51 PMJhevon
haha, stop guessing, and solve it. a would have to be less than 1, of course, otherwise, if you raise it to the 38th power, you would get a number greater than or equal to 1, which is bad, since we have 1/2 on the left hand side

$\displaystyle \frac 12A_0 = A_0a^{38}$

$\displaystyle \Rightarrow \frac 12 = a^{38}$

Now, how would you solve for $\displaystyle a$ here. what must you do to get rid of that 38th power, and be left with just $\displaystyle a$ on the right side? - Jun 29th 2008, 01:52 PMmankvill
- Jun 29th 2008, 01:58 PMJhevon
- Jun 29th 2008, 02:01 PMmankvill
- Jun 29th 2008, 02:10 PMJhevon
- Jun 29th 2008, 02:11 PMmankvill
(Hi)

2nd part: How much of a 4 gram sample would be left after 10 seconds? (Wondering) - Jun 29th 2008, 02:13 PMJhevon
- Jun 29th 2008, 02:17 PMmankvill
- Jun 29th 2008, 02:21 PMJhevon
- Jun 29th 2008, 02:23 PMmankvill