Answer:
5.7 kg of silver
Explanation:
This data 91.0% silver by mass means, that in 100 g of silver dollar, 91 g are silver.
Let's work with a rule of three. Previously, convert g to kg (/1000)
100 g = 0.1kg
If in 0.1 kg we have 91 grams of Ag
In 6.34kg we would have (91 . 6.34)/0.1 = 5769.4 grams of Ag
This can be converted to kg.
5769.4 g = 5.7 kg