Question

There are two alloys of gold and silver . In the first alloy, there is twice as much gold as silver , and in the second ally there is 5 times less gold than silver. How many times more must we take of the second alloy than the first in order to obtain a new alloy in which there would be twice as much silver as gold ?

Answer 1

Let A and B the first and second alloy weights respectively

x=% of bronze in alloy B

We know that B contains no GOLD.

.07A=.05(A+B)

B=.4A

substituting,

.9A+.4Ax=.85(A+.4A

x=.725=72.5%