-. A collection of 40 coins is made up of nickels and dimes and is worth $2.60. Find how many were quarters and how many were nickels.

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Step-by-step explanation:

Let d represent the number of dimes. Then 40-d is the number of nickels. The value is ...

  0.10d +0.05(40 -d) = 2.60

  0.05d = 0.60 . . . . . subtract 2.00

  d = 0.60/0.05 = 12 . . . . . the number of dimes

  40 -d = 40 -12 = 28 . . . . .the number of nickels

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There are 0 quarters. There are 28 nickels.

step-by-step explanation:

infinity is the answer

delaney would like to make a 5lb nut mixture that is 60% peanuts and 40% almonds.

she has several pounds of peanuts and several pounds of a mixture that is 20% peanuts and 80% almonds.

let 'p' represent the number of pounds of peanuts needed to make the new mixture, and  

let 'm' represent the number of pounds of the 80% almond-20% peanut mixture.

:

p + m = 5

therefore

m = (5-p)

write an equation based on the percent of peanuts

1p + .2m = .6(5)

replace m with (5-p)

p + .2(5-p) = .6(5)

p + 1 - .2p = 3

p - .2p = 3 - 1

.8p = 2

p = 2/.8

p = 2.5 lbs of peanuts required

then

5 - 2.5 = 2.5 lbs of the peanut/almond mixture required

:

a) what is the system that models this situation?

p + m = 5

1p + .2m = .6(5)