<PRE><B>Question 304982</B>
 How much silver valued at $4 per gram must be mixed with gold valued at $24 per gram to obtain 30 grams of alloy worth $12.00 per gram? 
Sat prep. Question.
Ans. 18grams
------------------------
Equations:
Quantity Eq::::  s + g = 30 grams
Value Eq::::::: 4s +24g = 12*30 dollars
-------------------------------------------
Solving by Elimination:
Divide thru the Value Eq. by 4 to get:
s + 6g = 90
---
Subtract the Quantity Eq. from that to get:
5g =60
g = 12 grams (amt. of gold needed in the mixture)
----
Since s+g = 30, s = 18 grams (amt. of silver needed in the mixture)
====================================================================
Cheers,
Stan H.
================= </PRE>