Question

A scientist makes a type of brass by mixing copper and zinc in the ratio of 8 to 2. How many kilograms of copper and zinc does he need to make 40 kilograms of brass?
A.
24 kilograms of copper, 16 kilograms of zinc
B.
16 kilograms of copper, 24 kilograms of zinc
C.
8 kilograms of copper, 32 kilograms of zinc
D.
32 kilograms of copper, 8 kilograms of zinc

Answer 1

To solve the problem, we start with the ratio of copper to zinc, which is 8:2. This can be simplified to 4:1. This means that for every 5 parts of the mixture (4 parts copper + 1 part zinc), 4 parts are copper and 1 part is zinc.

Now, let's calculate how many parts there are in a total of 40 kilograms of the brass mixture.

The total number of parts in the ratio is:
\[ 4 + 1 = 5 \text{ parts} \]

To find the weight of each part:
\[ \text{Weight of each part} = \frac{40 \text{ kg}}{5} = 8 \text{ kg} \]

Now we can find the weights of copper and zinc:

1. **Copper**:
\[ \text{Weight of copper} = 4 \text{ parts} \times 8 \text{ kg/part} = 32 \text{ kg} \]

2. **Zinc**:
\[ \text{Weight of zinc} = 1 \text{ part} \times 8 \text{ kg/part} = 8 \text{ kg} \]

Thus, to make 40 kilograms of brass, the scientist needs:
- 32 kilograms of copper
- 8 kilograms of zinc

The correct answer is:
**D. 32 kilograms of copper, 8 kilograms of zinc**