In a class, 2/7 of the students are boys and the rest are girls. If 1/4 of the boys and 3/4 of the girls are present, then what part of the total number of students is absent?

17/28

17/25

11/28

None of these

Let's assume the total number of students is 28x (LCM of 7 and 4 is 28).

Number of boys = (2/7) × 28x = 8x

Number of girls = 28x - 8x = 20x

Number of boys present = (1/4) × 8x = 2x

Number of boys absent = 8x - 2x = 6x

Number of girls present = (3/4) × 20x = 15x

Number of girls absent = 20x - 15x = 5x

Total number of students absent = 6x + 5x = 11x

Part of the total number of students absent = 11x / 28x = 11/28