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In a class of 20 students, 7 were wearing a white shirt. In the same class, 14 students had on blue jeans. Eyewitnesses all stated that the suspect was in the class, and wearing both a white shirt and blue jeans. According to the laws of probability, what percent of the class could be the suspect?
a. 15% b. 25% c. 35% d. 45%
how to solve this problem?