Problem
A coffee shop creates its house brand by mixing $8 / 13$ of locally produced coffee and $5 / 13$ of imported coffee. Among the imported coffee, $3 / 5$ is from Latin America and 1/3 of this Latin American Coffee is from Costa Rica. If 80 kilograms of locally produced coffee was used in the house brand, how much Costa Rican coffee is in the house brand? a. $10.0 \mathrm{~kg}$ b. $30.0 \mathrm{~kg}$ c. $40.0 \mathrm{~kg}$ d. $20.0 \mathrm{~kg}$ e. $5.0 \mathrm{~kg}$
Solution
Step 1 ：Let's find the total amount of coffee in the house brand: \(\frac{80}{8/13} = 130\text{ kg}\)
Step 2 ：Next, find the amount of imported coffee: \(130\times\frac{5}{13} = 50\text{ kg}\)
Step 3 ：Then, find the amount of Latin American coffee: \(50\times\frac{3}{5} = 30\text{ kg}\)
Step 4 ：Finally, find the amount of Costa Rican coffee: \(30\times\frac{1}{3} = 10\text{ kg}\)
Step 5 ：\(\boxed{10.0\text{ kg}}\) (Option a)
