NMOS 2010 Q14

Q14. The ratio of male students to female students in a primary school is 5 : 4. The ratio of students who wear spectacles to students who do not is 11:1. Given that 64% of the students who do not wear spectacles are female, find the percentage of female students who do not wear spectacles.


M : F = 5 : 4 = 20 : 16


S : N = 11 : 1 = 33 : 3



64/100 x 3 = 1.92 u



1.92/16 x 100% = 12% -- Female who do not wear spectacles.