Grade 7 Mixture Problems Worksheet

Grade 7 Mixture Problems

Read each problem carefully and solve for the unknown quantity. Show all your work.

1. A chemist has 20 liters of a solution which is 30% acid. How much pure acid should be added to make it a 50% acid solution?

2. If you mix 5 kg of nuts costing $6/kg with 10 kg of nuts costing $3/kg, the total cost of the mixture will be $ .

3. To dilute a 70% alcohol solution to a 40% alcohol solution, you need to add   water.

4. A candy store mixes two types of candy. One type sells for $2.50 per pound, and the other sells for $4.00 per pound. How many pounds of the cheaper candy should be mixed with 5 pounds of the more expensive candy to sell the mixture for $3.00 per pound?

5. A coffee shop blends two types of coffee beans. One type costs $12 per pound and the other costs $18 per pound. If they want to make 30 pounds of a blend that costs $14 per pound, how many pounds of each type of coffee bean do they need?

6. When mixing two solutions of different concentrations, the final concentration will always be between the two initial concentrations.