This question wants the total number of students in a class where 80% take Statistics, 45% take Mathematics, every student takes at least one of the two, and 40 students take both. We can check each option by testing whether 25% of that total equals 40, since the students who take both subjects make up 80% + 45% - 100% = 25% of the class.
Only 160 satisfies the condition that 25% of the class equals the 40 students who took both subjects.
Therefore, the correct answer is 160.
This question gives the total class as unknown, with every student taking at least one of Statistics or Mathematics, so the class splits into three non-overlapping groups: students who took only Statistics, students who took only Mathematics, and the 40 students who took both. Let \( T \) be the total number of students. Since 80% of \( T \) took Statistics and 45% of \( T \) took Mathematics, and everyone took at least one subject, by inclusion-exclusion the number taking both is \( 0.8T + 0.45T - T = 0.25T \). Setting this equal to the given 40 students, \( 0.25T = 40 \), so \( T = 160 \). Let's check each option against this equation to confirm.
Only \( T = 160 \) satisfies the equation \( 0.25T = 40 \) obtained from inclusion-exclusion of the two subject groups.
Therefore, the correct answer is 160.
