SOLUTION: i need help understanding solving word problems and how to read it and write it out in expression formula one snack mix contains nuts, candy and cereal and 10% of the weight of

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: i need help understanding solving word problems and how to read it and write it out in expression formula one snack mix contains nuts, candy and cereal and 10% of the weight of       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 544061: i need help understanding solving word problems and how to read it and write it out in expression formula
one snack mix contains nuts, candy and cereal and 10% of the weight of the mix is cereal. in nother similar mix, 40% of the weight mix is cereal. if you were to make 40 pounds of mix with 25% cereal by combinding some of each of these, how many pounds of the 10% cereal mix would you need?
i need help

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = pounds of the 10% cereal mix needed
Let +b+ = pounds of the 40% cereal mix needed
given:
+.1a+ = pounds of cereal in 10% cereal mix
+.4b+ = pounds of cereal in 40% cereal mix
--------------------------------------
In words:
( total pounds of cereal in final mix ) / ( total pounds in final mix ) = 25%
(1) +a+%2B+b+=+40+
(2) +%28+.1a+%2B+.4b+%29+%2F+40+=+.25+
-------------------------
(2) +.1a+%2B+.4b+=+.25%2A40+
(2) +.1a+%2B+.4b+=+10+
(2) +a+%2B+4b+=+100+
Subtract (1) from (2)
(2) +a+%2B+4b+=+100+
(1) +-a+-+b+=+-40+
+3b+=+60+
+b+=+20+
and, since
(1) +a+%2B+b+=+40+
(1) +a+%2B+20+=+40+
(1) +a+=+20+
20 pounds of the 10% cereal mix is needed
check answer:
(2) +%28+.1a+%2B+.4b+%29+%2F+40+=+.25+
(2) +%28+.1%2A20+%2B+.4%2A20+%29+%2F+40+=+.25+
(2) +%28+2+%2B+8+%29+%2F+40+=+.25+
(2) +10%2F40+=+.25+
(2) +10+=+10+
OK