Question 394370: How much gold valued at $12 per gram must be mixed with silver valued at $.80 per gram to obtain 20g of an alloy worth $5 per gram?
I set up the equations as s= silver g= gold
s + g = 20
.8s + 12g = 5 I get s= 20.98 g = -.98
This doesn't seem right. Can you please help?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! How much gold valued at $12 per gram must be mixed with silver valued at $.80 per gram to obtain 20g of an alloy worth $5 per gram?
let x = grams of gold used
then, 20-x = grams of silver used
note that the number of grams of the alloy must add up to the weight of the silver and gold used, ie, x+(20-x) = 20
we then set up an equation, equating cost,($/gram * no. of grams)
12x+.8(20-x)=5*20
12x+16-.8x=100
11.2x=100-16=84
x=84/11.2
x=7.5 grams (gold used)
20-x=12.5 grams (silver used)
ans:grams of gold that must be mixed with silver = 7.5
|
|
|
