On camera, Ruby Rai, 17, who topped Bihar's Class 12 exams in the Arts stream, says political science, a subject she virtually aced, teaches cooking. Another student from her junior or intermediate college, who placed as Bihar's Science topper, was not able to answer elementary questions like the link between water and H20. The students were interviewed by local channels after their results were declared last week. So the 10 toppers among the nearly 15 lakhs students in Bihar will now take a new exam within the next week, an embarrassed government has said.