Question

Mavis ate 3/10
of her birthday cake. She decided to give the brother 2/3
of what is left of the cake.

Answer 1

Mavis ate $\frac{3}{10}$ of the birthday cake

i.e $1- \frac{3}{10}$ $= \frac{7}{10}$

$\frac{2}{3}$ what was left of the cake she decided to give her brother, i.e.

$\frac{7}{10}×\frac{2}{3}$ $= \frac{7}{15}$ was eaten by her brother,

$\frac{7}{10}$ was left and brother ate $\frac{7}{15}$ .

So $\frac{7}{10}-\frac{7}{15}=\frac{7}{30}$ was left.