How many pounds of nuts did Jena use in the case below?Jena mixed 8 lb of raisins that cost 2.50 per lb with nuts that cost 3.75 per lb to obtain a mixture that costs 3.35 per lb.

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justaguide eNotes educator| Certified Educator

Jena mixed 8 lb of raisins that cost 2.50 per lb with nuts that cost 3.75 per lb to obtain a mixture that costs 3.35 per lb.

Let the number of pounds of nuts used by Jena be X. As the cost of the final mixture is 3.35 per lb, the cost of the mixture is 3.35*(X + 8)

3.35*(X + 8) = 2.5*8 + X*3.75

=> X*(3.75 - 3.35) = 26.8 - 20

=> X = 6.8/0.4

=> X = 17

Jena used 17 pounds of nuts to make the mixture.

najm1947 | Student

Let the weight of nuts mixed with 8 pounds of raisin be x, to make and 8+x punds of mixture

then total cost of mixture = 2.50*8+3.75x = 3.35*(8+x)

=> 20+3.75x = 26.80+3.35x

=> 3.75x-3.35x = 26.8-20

=> 0.40x = 6.8

=> x = 6.8/0.40 = 17 pounds

She used 17 pounds of nuts to get the cost of 3.35 per pound.