SOLUTION: 1 lb. soy meal has 14% protein 1 lb. corn meal has 7% protein How many pounds of each is mixed together for a total weight of 280 lbs. with a 11% protein

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: 1 lb. soy meal has 14% protein 1 lb. corn meal has 7% protein How many pounds of each is mixed together for a total weight of 280 lbs. with a 11% protein      Log On


   

Question 429790: 1 lb. soy meal has 14% protein
1 lb. corn meal has 7% protein
How many pounds of each is mixed together for a total weight of 280 lbs. with a 11% protein
Found 2 solutions by mananth, josmiceli:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
percent ----------------quantity
Soy meal 14 ----------------x pounds
Corn meal 7 ----------------280-x pounds
Total 11.00% ----------------280
14x+7(280-x)=11*280
14x+1960-7x=3080
14x-7x=3080-1960
7x=1120
/7
x=160 pounds Soy meal
120 pounds corn meal

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let a = pounds of soy meal needed
Let b = pounds of corn meal needed
given:
(1) +%28+.14a+%2B+.07b+%29+%2F+280+=+.11+
(2) +a+%2B+b+=+280+
------------------
(1) +.14a+%2B+.07b++=+.11%2A280+
(1) +.14a+%2B+.07b++=+30.8+
(1) +14a+%2B+7b++=+3080+
Multiply both sides of (2) by 7
and subtract (2) from (1)
(1) +14a+%2B+7b++=+3080+
(2) +-7a+-+7b+=+-1960+
+7a+=+1120+
+a+=+160+
and, since
(2) +a+%2B+b+=+280+
+160+%2B+b+=+280+
+b+=+120+
160 pounds of soy meal is needed
120 pounds of corn meal is needed