## GMAT Quantitative Review

## 3.0 Math Review

### 3.4 Word Problems

### 3. Mixture Problems

In mixture problems, substances with different characteristics are combined, and it is necessary to determine the characteristics of the resulting mixture.

*Example 1:* If 6 pounds of nuts that cost $1.20 per pound are mixed with 2 pounds of nuts that cost $1.60 per pound, what is the cost per pound of the mixture?

*Solution:* The total cost of the 8 pounds of nuts is

.

The cost per pound is .

*Example 2:* How many liters of a solution that is 15 percent salt must be added to 5 liters of a solution that is 8 percent salt so that the resulting solution is 10 percent salt?

*Solution:* Let *n* represent the number of liters of the 15% solution. The amount of salt in the 15% solution [0.15*n*] plus the amount of salt in the 8% solution [(0.08)(5)] must be equal to the amount of salt in the 10% mixture . Therefore,

Two liters of the 15% salt solution must be added to the 8% solution to obtain the 10% solution.