Question

In a metal alloy, the ratio of zinc to copper is 3 to 13. If there are 455 lb of copper, how much zinc is there?

a) 105 lb
b) 35 lb
c) 9 lb
d) 39 lb

Answer 1

Given a ratio of 3 parts zinc to 13 parts copper and 455 lb of copper, each part is 35 lb. Multiplying by 3 parts of zinc gives us 105 lb of zinc.

So, the correct answer is A.

Step-by-step explanation:

The student's question involves finding the amount of zinc in a metal alloy when the ratio of zinc to copper is given, and the mass of copper is known. In this case, the ratio is 3 parts zinc to 13 parts copper. If there are 455 lb of copper, then each 'part' represents 455 lb divided by 13, which is 35 lb. Therefore, since the ratio indicates that there are 3 parts of zinc, we multiply 35 lb by 3 to find the amount of zinc.

Calculating this gives us: 35 lb/part × 3 parts = 105 lb of zinc.

Thus, the correct answer is 105 lb of zinc, which corresponds to option (a).