Question

(grade 9 academic math) last night your sister made cake for dessert. she cut the cake into 15 equal slices but only 13 slices were eaten. the next day, you ate 1/5 of the remaining cake for a snack. what fraction of the cake was left?

Answer 1

Answer:

$\frac{8}{75}$

Step-by-step explanation:

If the cake was initially cut into 15 equal slices and 13 of those were eaten:

$\frac{15}{15}-\frac{13}{15}=\frac{2}{15}$

$\frac{2}{15}$ slices would be left

$\frac{1}{5}of\frac{2}{15}=\frac{1}{5}*\frac{2}{15}=\frac{2}{75}$

Since you only had 2/15 left and ate 2/75, we can subtract these amounts to find the remaining amount of cake.  However, fractions can only be subtracted if they have the same denominator:

$\frac{2}{15}=\frac{10}{75}$

$\frac{10}{75}-\frac{2}{75}=\frac{8}{75}$