Marie gave away \(\frac{2}{5}\) to her daughter and \(\frac{2}{5}\) to her son.<br><br>
[[model:questions/solutions/q10648.png]]<br><br>
&bull; Total given away: \(\frac{2}{5} + \frac{2}{5} = \frac{4}{5}\)<br>
&bull; Whole cake = 1 = \(\frac{5}{5}\)<br>
&bull; Marie ate: \(\frac{5}{5} - \frac{4}{5} = \frac{1}{5}\)<br><br>
Marie ate \(\frac{1}{5}\) of the cake.<br>
Check: \(\frac{2}{5} + \frac{2}{5} + \frac{1}{5} = \frac{5}{5} = 1\) ✓<br><br>
Final Answer: \(\frac{1}{5}\)