The average of marks obtained by a student in some subjects is 80. If the average without the highest and the lowest marks is calculated, it is 81. If the highest obtained score is 92, and the number of subjects is equal to the product of the first even prime number and the second odd prime number then find the lowest marks.

Number of subjects = first even prime (2) × second odd prime (3) = 6 subjects incorrectly stated in problem - first even prime is 2, second odd prime is 5, so 2×5 = 10. Let sum of 10 marks = S. Average = 80, so S = 800. Without highest (92) and lowest (L marks), sum = S - 92 - L = 708 - L. Average of 8 marks = 81, so (708 - L)/8 = 81. Solving: 708 - L = 648, so L = 60.