If the number of boys in a class are 8 times the number of girls, which value can never be the total number of students?  Choose the most appropriate option:
A) 27  B) 45  C) 81  D) 42  E) 56
Explanation :   Let the number of girls = x and the number of boys = 8x   Then, total number of students = x + 8x = 9x   i.e., the total number of students must be a multiple of 9   From the given choices, 42 cannot be a multiple of 9.   Hence, 42 cannot be the total number of students.   Answer : 42
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If the number of boys in a class are 8 times the number of girls, which value can never be the total number of students?