Question 118939: 1. If an alloy containing 30% silver is mixed with a 55% silver alloy to get 800 pounds of 40% alloy, how much of each mixture must he use?
2. Pia wishes to make bouquets of mixed spring flowers. Each bouquet should be made up of tulips at 30 pesos a bunch and roses at 21 pesos a bunch. How many bunches of each flower should she use to make 15 bunches that can be sold at 24 pesos per bunch?
3. A store manager wishes to reduce the price on her cooked peanuts by mixing two grades. If he has 50 pounds of peanut that sells for 10 pesos per pound, how much peanut worth 6 pesos per pound must he mix with it so that he can sell the final mixture for 8.50 pesos per pound?
4. How many grams of water must be added to 100grams of a 40% acid solution in order to produce a 20% acid solution?
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Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! 1. If an alloy containing 30% silver is mixed with a 55% silver alloy to get 800 pounds of 40% alloy, how much of each mixture must he use?
:
Let x = amt of 55% alloy required:
Then
(800-x) = amt of 30% alloy required
:
Write a silver amt equation:
.55x + .30(800-x) = .40(800)
:
.55x + 240 - .3x = 320
:
.55x - .30x = 320 - 240
:
.25x = 80
:
x = 80/.25
:
x = 320 lb of 55% alloy
then
800 - 320 = 480 lb of 30% alloy
:
You can check solutions in the original equation
:
:
2. Paula wishes to make bouquets of mixed spring flowers. Each bouquet should be made up of tulips at 30 cents a bunch and roses at 21 cents a bunch. How many bunches of each flower should she use to make 15 bunches that can be sold at 24 cents per bunch?
:
Let x = no. of 30 cent bunches
Then
(15-x) = no. of 21 cent bunches
:
30x + 21(15-x) = 24(15)
:
30x + 315 - 21x = 360
:
30x - 21x = 360 - 315
:
9x = 45
:
x = 45/9
:
x = 5 ea 30 cent bunches
then
(15-5) = 10 ea 21 cent bunches
:
:
3. A store manager wishes to reduce the price on his cooked peanuts by mixing two grades. If he has 50 pounds of peanuts that sells for 10 cents per pound, how much peanuts worth 6 cents per pound must he mix with it so that he can sell the final mixture for 8.5 cents per pound?
:
Another typical mixture problem:
:
Let x = amt of 10 cent peanuts
then
(x + 50) = resulting amt of 8.5 cent peanuts
:
10(50) + 6x = 8.5(x+50)
:
500 + 6x = 8.5x + 425
:
6x - 8.5x = 425 - 500
:
-2.5x = - 75
:
x = -75/-2.5
:
x = +30 lbs of 6 cent peanuts
:
:
4. How many grams of water must be added to 100 grams of a 40% acid solution in order to produce a 20% acid solution?
:
You should be able to do these now, Here is the equation:
:
.4(100) = .2(100+x)
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