Bunuel
At a certain university, there are s students, w of whom are female and m of whom are male. The number of female physics students is denoted by \(p_w\) and is exactly 12% of the female enrollment. Similarly, the number of male physics students is denoted by \(p_m\) and is exactly 25% of the male enrollment. If the overall number of physics students is denoted by p, which of the following must be true?
A. \(p_w<p_m\)
B. w>0.06s
C. w<p<m
D. \(p_m=0.125s\)
E. 0.12s<p<0.25s
The only challenging part of this question is the number of variables introduced.
Total no of students - s, Female - w, Male - m
12% of females (w) take physics. \(p_w\)
25% of males (m) take physics. \(p_m\)
No of students who have taken physics = p
Overall percentage of students taking physics = (p/s)*100
This reminds one of weighted average. 12% of females take physics. 25% of male take physics. What % of total have taken physics. The overall percentage will lie between 12 and 25. If all students were male, 25% of them would have taken physics. If all were female, 12% would have taken physics. But since they are a mix, the overall percentage will lie between 12 and 25.
Hence (E) is correct.
E. 0.12s<p<0.25s
.12 < p/s < 0.25
12/100 < p/s < 25/100