This question needs to calculate the number of people who can pass the certification among all the people who take the exam. The total number of people known to take the exam is: 42. The pass rate of known subject A is 0.85. The pass rate of known subject B is 0.4. It is known that the pass rate of subject C is 0.4. It is known that the pass rate of subject D is 0.5. The pass rate of known subject E is 0.45. According to the description of the topic, as long as one subject fails, it will not pass the certification. Therefore, the conditions for passing the certification are: the number of people who pass the certification = the number of people who pass each subject = the product of the passing rate of each subject: 0.85× 0.4× 0.4× 0.5× 0.45 = 0.03060.85 \ multiplied by 0.4 \ multiplied by 0.4 \ multiplied by 0.5. Multiplied by 0.45 = 0.03060.85× 0.4× 0.4× 0.5× 0.45 = 0.0306, the number of people who finally passed the certification is: 42 × 0.0306 = 1.285242 \ multiplied by 0.0306 =1.24.