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# The CA SOLVE Approach to Word Problems for CBEST Exam Study Guide (page 2)

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Updated on Mar 29, 2011

#### E Stands for Eliminate

Eliminate answers you know are wrong. You may also spend a short time checking your answer if there is time.

#### Sample Question

Solve this problem using the CA SOLVE steps.

1. There are 651 children in a school. The ratio of boys to girls is 4:3. How many boys are there in the school?
1. 40
2. 325
3. 372
4. 400
5. 468

1. Subject Experience: You know that 4 and 3 are only one apart and that 4 is greater. You can conclude from this that boys are a little over half the school population. Following up on that, you can cut 651 in half and eliminate any answers that are less than half. Furthermore, since there are three numbers in the problem and two are paired in a ratio, you can conclude that this is a ratio problem. Then you can think about what methods you used for ratio problems in the past.
2. Organize: The clue word total means to add. In the context in which it is used, it must mean girls plus boys equals 651. Also, since boys is written before girls, the ratio should be written Boys: Girls.
3. Live: Picture a group of three girls and four boys. Now picture more of these groups, so many more that the total would equal 651.
4. View: If there were only 4 boys and 3 girls in the school, there would still be a ratio of 4 to 3. Think of other numbers that have a ratio of 4:3, like 40 and 30. If there were 40 boys and 30 girls, there would be 70 students in total, so the answer has to be more than 40 boys. Move on to 400 boys and 300 girls—700 total students. Since the total in the problem is 651, 700 is too large, but it is close, so the answer has to be less than 400. This would narrow your choices to two.
5. Eliminate: Since you know from the previous step that the number of students has to be less than 400, you can eliminate choices d and e. Since you know that the number of boys is more than half the school population, you can eliminate choices a and b. You are left with choice c, the correct answer.

### Quick Tips and Tricks

Below is a miscellaneous list of quick tips to help you solve word problems.

On some problems, you can plug in given answers to see which one works in a problem. Start with choice c. Then if you need a larger number, go down, and if you need a smaller answer, go up. That way, you don't have to try them all. Consider the following problem:

1. One-fifth of what number is 30?
1. 6
2. 20
3. 50
4. 120
5. 150

Try c: of 50 is 10. A larger answer is needed.

Try d: of 120 is 24. Not yet, but getting closer.

Try e: of 150 is 30—Bingo!