Question

There is an alloy (A) of silver and copper. A certain weight of this alloy is mixed with 15 kg of pure Silver and melted. The new alloy (B) contains $90\%$ of silver. If the same weight of alloy (A) is mixed with 10kg of a $90\%$ silver alloy, the new alloy (C) is found to contain $84\%$ silver. Find the percentage of silver in (A).

• A. 80%
• B. 90%
• C. 75%
• D. 84%
• E. 72%

Answer 1

The correct option is A 80%

Use alligation and then the answer options

Let the percentage of silver in alloy A be a

Now substitute values from answer options such that all the criteria are satisfied. Answer is option (a) as shown below