Elaborative interrogation, which prompts students to answer why-questions placed strategically within informational text, has been shown to increase learning comprehension through reading. In this study, elaborative interrogation why-questions requested readers to explain why paraphrased statements taken from a reading were "true." Although previous research in elaborative interrogation has examined the effect of utilizing these why-questions while reading biology content, they have not been explored with chemistry text or chemistry textbooks that include worked example problems, according to a review of the literature. This study investigated the effect of answering elaborative interrogation why-questions placed adjunct to worked examples which were embedded within a section of a college chemistry textbook, compared with the commonly used study strategy of rereading the same text as a placebo-control. A randomized two-group posttest only design was used in this study. Specifically, the ability to solve quantitative chemistry problems in terms of a problem solving posttest requiring comprehension (dependent variable) was estimated for both groups and statistically compared. The subjects in this research were 74 students enrolled in an introductory chemistry course at a community college in the southwestern United States. Prior chemistry knowledge, mathematics skills, and verbal ability were also measured and statistical methods were employed to assess their correlations with posttest results in both groups. The use of elaborative interrogation why-questions was found to significantly benefit students' quantitative chemistry problem solving requiring comprehension compared to the rereading strategy, even after the effects of prior chemistry knowledge and mathematics skill (factors that were statistically determined to be significant predictors of posttest score) were statistically controlled.