Calculate the moles of acid and conjugate base needed
Since it is a buffer solution, the volume is constant ($V =\pu{0.1 L}$), hence
$$
\frac{c(b)}{c(a)} = \frac{n(b)}{n(a)}\overset{calc.}{=}0.72
$$
 and with
$$
n_{\text{tot}}=n(b)+n(a) \overset{\text{def}.}{=}\pu{0.05 mol}\\
n(a)=\frac1{1.72}\cdot\pu{0.05 mol}\\
n(b)=\frac{0.72}{1.72}\cdot\pu{0.05 mol}
$$
Then $$m=M\cdot n$$ and you should be fine.