SOLUTION: A chemist has a 15% silver alloy and a 30% silver alloy. How much of each alloy is need to be mixed to obtain 25 kg of an alloy that is 20% silver? (show work)

Question 630992: A chemist has a 15% silver alloy and a 30% silver alloy. How much of each alloy is need to be mixed to obtain 25 kg of an alloy that is 20% silver? (show work)
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
A chemist has a 15% silver alloy and a 30% silver alloy. How much of each alloy is need to be mixed to obtain 25 kg of an alloy that is 20% silver? (show work)
.
Let x = amount (kg) of 15% silver
then
25-x = amount (kg) of 30% silver
.
.15x + .30(25-x) = .20(25)
.15x + 7.5-.30x = 5
7.5-.15x = 5
-.15x = -2.5
x = -2.5/(-.15)
x = 2.5/(.15)
x = 250/15
x = 50/3
x = 16.67 kg (15% silver)
.
30% silver:
25-x = 25-16.67 = 8.33 kg
RELATED QUESTIONS
How many grams of 50% silver alloy and a 10% silver alloy must be mixed to obtain 24... (answered by robertb)

An alloy containing 30% silver is mixed with a 55% silver alloy to get 800 pounds of 40%... (answered by josgarithmetic)

A jeweler has 30 oz of an alloy consisting of 60 percent gold and 40 percent silver. How... (answered by stanbon)

a smelter ha 640 pounds of a 50% silver alloy and 200 pounds of a 20% alloy. how much of... (answered by stanbon)

A silversmith has two alloys, one containing 70% silver and the other 40% silver. How... (answered by Maths68)

Sterling silver is 92.5% pure silver. How many grams of sterling silver must be mixed to... (answered by jorel1380)

A 25% silver alloy is to be melted with a 55 % silver alloy. How many grams of each... (answered by richwmiller)

How many ounces of a base metal (no silver) must be alloyed with 100 ounces of 39% silver (answered by TimothyLamb)

A foundry has been commissioned to make souvenir coins. The coins are to be made from an... (answered by ikleyn)