a metal alloy weighing 7 lb. and containing 40% silver is melted and mixed with 8 lb. of pure silver. what percent of resulting alloy is silver?

Question

help SOS i hate math and i dont get this

Answer 1

If we combine the metal alloy with the pure silver:

 

7 lbs + 8 lbs = 15 lbs in total.

 

However, only 40% of the metal alloy is silver: 7 lbs (0.40) = 2.8 lbs of silver in metal alloy

 

So, the total amount of silver is:

 

2.8 lbs from metal alloy weighing 7 lbs

 

8 lbs of silver from the pure silver sample weighing 8 lbs

 

total weight of silver = 2.8 lbs + 8 lbs = 10.8 lbs

 

total weight in silver / total weight of all materials = 10.8 lbs / 15 lbs = 0.72% of resulting alloy is silver.