The equation for exponential decay is [tex]y=a*b^x[/tex], where a is the initial amount, b = 1 + r (the growth rate as a decimal number) and x is the number of time periods (in this case, minutes). Substituting the information we have:
[tex]y=430(1+-0.274)^1^9
\\=430(1-0.274)^1^9
\\=430(0.726)^1^9=0.98[/tex]. To the nearest tenth of a gram, this would be 1.0 grams.