That problem could answered easyly in Matlab,
We know that [tex]c=c_0e^{\frac{t}{k}}[/tex]
So whit this program we can make it,
figure('color','white')
initial=10;
decay_rate=1.48
time=[0:0:1:5];
concen=initial*exp(-time/decay_rate);
plot(time,concen)
grid
title('Decay of the Isotope A')
xlabel('Time (hours'))
ylabel('concentration in grams')