Answer: Option 'A' is correct.
Step-by-step explanation:
Since we have given that
In 80 ounces, 10 ounces of gold.
So, Proportion of gold would be
In new alloy of 5 ounces, one fifth of ounce is gold, so, it becomes,
it means 0.2 ounce is gold in 5 ounces.
So, proportion of gold would be
Let x be the amount of silver is to be added.
According to question, it becomes,
Hence, Option 'A' is correct.