[cinder06]

I'm taking chemistry , and need some help on this question.

The daily dose of ampicillin for the treatment of an ear infection is 115mg ampicillin per kilogram of body weight (115mg/kg), What is the daily dose for a 27lb child?

So far I've done this, but am not sure if its the right answer. And significant figures matter.

27lb x 1kg = 12kg x 115mg = 1380 mg
 _ _ --------
_  __2.20lb

I set it up in a conversion factor, that 1kg equals 2.20lbs, and the lbs symbols cancel each other out, so I end up taking 27 divided by 2.20 and I get 12 kg and since its 115mg per every kg I took 12kg multiple 115mg and got 1380 mg as the dose for a 27lb child.

Am I right??? I have to use significant figures.

[Ak]

your method is correct but i would suggest not rounding off until the end...so instead of 12kg u'd have 12.2727 and for significant figures i think the answer should be expressed to 2 digits because of the 27lb child (uses 2 sig figs)