In a college, 40% of the students were allotted group A, 75% of the remaining were given group B and the remaining 12 students were given group C. Then the number of students who applied for the groups is

Group A = 40%

Group $mathrm{B} equiv frac{60 imes 75}{100}=45 \%$

Group C = 15%

If the total number of students be x, then

$frac{x imes 15}{100}=12$

$Rightarrow x=frac{12 imes 100}{15}=80$