SOLUTION: Brand X sells 21 oz. bags of mixed nuts that contain 29% peanuts. To make their product they combine Brand A mixed nuts which contain 35% peanuts Brand B mixed nuts which contain 2

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Brand X sells 21 oz. bags of mixed nuts that contain 29% peanuts. To make their product they combine Brand A mixed nuts which contain 35% peanuts Brand B mixed nuts which contain 2      Log On


   



Question 198835: Brand X sells 21 oz. bags of mixed nuts that contain 29% peanuts. To make their product they combine Brand A mixed nuts which contain 35% peanuts Brand B mixed nuts which contain 25% peanuts. How much of each do they need to use?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let a= ounces of brand A they need
Let b= ounces of brand B they need
given:
.35a= ounces of peanuts in brand A
.25b= ounces of peanuts in brand B
a+%2B+b+=+21
.29%2A21+=+6.09= ounces of peanuts in final mixture
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In words:
(total ounces of peanuts) / (total ounces of mixture) = % peanuts
(1) a+%2B+b+=+21
(2) %28.35a+%2B+.25b%29+%2F+21+=+.29
Multiply both sides of (2) by 21
(2) .35a+%2B+.25b+=+6.09
Multiply both sides of (1) by .25
and subtract (1) from (2)
(2) .35a+%2B+.25b+=+6.09
(1) -.25a+-+.25b+=+5.25
.1a+=+.84
a+=+8.4
and, since
a+%2B+b+=+21
b+=+21+-+8.4
b+=+12.6
They need 8.4 ounces of brand A and 12.6 ounces of brand B
check answer:
(2) %28.35a+%2B+.25b%29+%2F+21+=+.29
(2) %28.35%2A8.4+%2B+.25%2A12.6%29+%2F+21+=+.29
%282.94+%2B+3.15%29+%2F+21+=+.29
6.09%2F21+=+.29
.29+=+.29
OK