An alloy contains zinc and copper in the ratio 7:9 . Find the weight of copper if it has 31.5 kg of zinc

copper = zinc * 9/7

To find the weight of copper in the alloy, we need to determine the weight of zinc and then use the given ratio to calculate the weight of copper.

Given that the ratio of zinc to copper is 7:9, we know that the sum of the ratio parts is 7 + 9 = 16.

Let's use this information to calculate the weight of copper.

1. Calculate the weight of zinc:
Since we know the weight of zinc is 31.5 kg, we can write the ratio as follows:
Zinc weight / Copper weight = 7 / 9

Let's set up a proportion to find the weight of zinc:
Zinc weight / 31.5 = 7 / 16

Now, we can solve for the weight of zinc:
Zinc weight = (31.5 * 7) / 16
Zinc weight = 13.8125 kg

2. Calculate the weight of copper:
To find the weight of copper, subtract the weight of zinc from the total weight of the alloy:
Copper weight = Total weight - Zinc weight
Copper weight = 31.5 kg - 13.8125 kg
Copper weight = 17.6875 kg

Therefore, the weight of copper in the alloy is 17.6875 kg.