Maria is mixing raisins and nuts to make 5 pounds of trail mix. Raisins cost $1.50, a pound and nuts cost $7 a pound. If Maria wants her cost for the trail mix to be $4.80 a pound, how many pounds of raisins and how many pounds of nuts should she use?

Respuesta :

Answer:

3 pounds of nuts, 2 pounds of raisins

Step-by-step explanation:

Write the equation by adding the total values, and solve for x to find the number of pounds of nuts.

7x + 1.5(5-x) = 5(4.80)

7x + 7.5 - 1.5x = 24

5.5x = 16.5

x = 3

Answer:

Maria should use 3 pounds of nuts and 2 pounds of raisins.

Step-by-step explanation:

Givens

  • Raisins cost $1.50 per pound.
  • Nuts cost $7 per pound.
  • Maria wants to make 5 pounds of trail mix, raisins and nuts all together.
  • The cost of the trail mix will be $4.80 per pound.

Let's call raisins [tex]R[/tex] and nuts [tex]N[/tex]. Also, [tex]M[/tex] will express the mix.

We know that [tex]M = R + N[/tex], because the mix is made from raisins and nuts. Where [tex]M=5[/tex]. So, the equation that represents this is

[tex]R+N=5[/tex]

Now, the equation that represents the cost is

[tex]1.50R+7N=4.80M[/tex] BUt, [tex]M=5[/tex], so

[tex]1.50R+7N=4.80(5)\\1.50R+7N=24[/tex]

Then, we isolate [tex]R[/tex] in the first equation to replace it into the second equation and solve for [tex]N[/tex]

[tex]R+N=5\\R=5-N[/tex]

[tex]1.50R+7N=24\\1.50(5-N)+7N=24\\7.5-1.50N+7N=24\\5.5N=24-7.5\\N=\frac{16.5}{5.5}\\ N=3[/tex]

Then, we replace this value in the first equation to find [tex]R[/tex]

[tex]R+N=5\\R+3=5\\R=5-3\\R=2[/tex]

Therefore, Maria should use 3 pounds of nuts and 2 pounds of raisins.