Problema Solution

A metallurgist has 30 grams of a metal alloy that is 60% silver. How much pure silver must be added to the alloy to obtain a mixture that is 70% silver?

Answer provided by our tutors

From the given information, we can write:


30(.6)+x(1)=(30+x)(.7)


Where .6, 1, and .7 are the percentages in fractional form of the various alloys and pure silver. 30 and 30+x are the respective amounts of the 60% and 70% alloy. 'x' is the amount of pure silver needed. Solving for x, we get:


x=10 grams