### Instruction: Victor and Kelsey have identical sandwiches. Victor eats $\frac{2}{5}$ of his sandwich. If Kelsey eats $\frac{15}{8}$ as much as Victor does, what fraction of her sandwich did she eat?### Response: I want to find the fraction of Kelsey's sandwich that she ate, so I need to relate it to the fraction of Victor's sandwich that he ate.
The problem says that Kelsey eats $\frac{15}{8}$ as much as Victor does, so that means I need to multiply Victor's fraction by $\frac{15}{8}$ to get Kelsey's fraction.
So, Kelsey's fraction is $\frac{2}{5} \times \frac{15}{8} = \frac{2 \times 15}{5 \times 8} = \frac{30}{40}$.
I can simplify this fraction by dividing both the numerator and the denominator by 10, and I get $\frac{30}{40} = \frac{3}{4}$.
So, Kelsey ate $\frac{3}{4}$ of her sandwich.