Mixture Problems

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Show your work for each problem.

1.
If you mix 10 liters of 20% salt solution with 10 liters of 40% salt solution, what is the concentration of the mixture?
1. a)25%
2. b)30%
3. c)60%
4. d)20%
2.
What is the key formula for solving mixture problems?
1. a)
2. b)
3. c)
4. d)
3.
When diluting a 50% acid solution with pure water, what happens to the concentration?
1. a)It decreases
2. b)It increases
3. c)It stays at 50%
4. d)It doubles
4.
A coffee shop mixes 8 kg of beans at 15 euros/kg with 12 kg of beans at 10 euros/kg. What is the price per kg of the blend?
1. a)13 euros/kg
2. b)11 euros/kg
3. c)12.50 euros/kg
4. d)12 euros/kg
5.
If you mix a 30% solution with a 70% solution, the resulting mixture must have a concentration:
1. a)Less than 30%
2. b)Between 30% and 70%
3. c)Greater than 70%
4. d)Equal to 100%
6.
How much pure alcohol is in 8 liters of a 25% alcohol solution? (Answer in liters)
7.
If 5 liters of 20% juice is mixed with 5 liters of 60% juice, what is the percentage of fruit in the mixture?
8.
How many liters of water must be added to 10 liters of 80% acid to create a 50% solution?
9.
A blend of 30 kg sells for 11 euros/kg. If premium coffee costs 14 euros/kg and standard costs 8 euros/kg, how many kg of premium coffee are in the blend?
10.
How many liters of 70% alcohol must be added to 12 liters of 40% alcohol to create a 55% solution?
11.
A chemist mixes 6 liters of 20% acid with 4 liters of 45% acid. Find the concentration of the mixture.
12.
A pharmacy needs 80 mL of a 12% iodine solution. They have 5% and 20% solutions. How many mL of each are needed?
13.
A store wants to create 50 kg of a nut mix priced at 16 euros/kg by mixing cashews at 20 euros/kg with peanuts at 10 euros/kg. How many kg of each?
14.
A lab has 15 liters of 60% alcohol. How many liters of pure water must be added to dilute it to 36%?
15.
How many liters of a 90% acid solution must be added to 20 liters of a 30% acid solution to create a 50% acid solution?
16.
A jeweler wants 40g of 18-karat gold (75% pure). She has 24-karat gold (100% pure) and 12-karat gold (50% pure). How many grams of each?
17.
A tea shop mixes tea at 24 euros/kg with tea at 16 euros/kg. If they want 25 kg of a blend priced at 18.40 euros/kg, how many kg of each tea?
18.
A chemist needs 200 mL of 35% acid. She only has 20% acid and 60% acid solutions. How many mL of each?