SOLUTION: ann and nancy use a metal alloy that is 16% copper to make jewerly. How many ounces of a 11% alloy must be mixed with a 24% allot to form 130 ounces of the desired alloy?

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: ann and nancy use a metal alloy that is 16% copper to make jewerly. How many ounces of a 11% alloy must be mixed with a 24% allot to form 130 ounces of the desired alloy?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 517417: ann and nancy use a metal alloy that is 16% copper to make jewerly. How many ounces of a 11% alloy must be mixed with a 24% allot to form 130 ounces of the desired alloy?
Found 2 solutions by richwmiller, josmiceli:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
x+y=130
.11x+.24y=.16*130

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let a = ounces of 11% alloy needed
Let b = ounces of 24% alloy needed
given:
(1) +a+%2B+b+=+130+
(2) +%28+.11a+%2B+.24b+%29+%2F+130+=+.16+
-----------------------------
(2) +.11a+%2B+.24b+=+.16%2A130+
(2) +.11a+%2B+.24b+=+20.8+
(2) +11a+%2B+24b+=+2080+
Multiply both sides of (1) by +11+
and subtract (1) from (2)
(2) +11a+%2B+24b+=+2080+
(1) +-11a+-+11b+=+-1430+
+13b+=+650+
+b+=+50+
and, since
(1) +a+%2B+b+=+130+
(1) +a+=+130+-+50+
(1) +a+=+80+
80 ounces of 11% alloy are needed
50 ounces of 24% alloy are needed
check:
(2) +%28+.11%2A80+%2B+.24%2A50+%29+%2F+130+=+.16+
(2) +%28+8.8+%2B+12+%29+%2F+130+=+.16+
(2) +20.8+=+.16%2A130+
(2) +20.8+=+20.8+
OK