The equation for exponential decay is 
, where <em>a</em> is the initial amount, <em>b</em> = 1 + <em>r</em> (the growth rate as a decimal number) and <em>x</em> is the number of time periods (in this case, minutes). Substituting the information we have:
. To the nearest tenth of a gram, this would be 1.0 grams.