PRENCENTILE QUESTION37 1/2% OF THE CANDIDATES IN AN EXAMINATIONWERE GIRLS. 75% of the boys & 62 1/2 % of the girls passed & 342 girls failed. The...

This means 37.5% of the girls failed. 
100%-62.5%=37.5%

So 342=37.5%(Total # of girls taking
test)

So Total # of girls taking the test = 342/(0.375)=912
Girls took the test.

Now 37.5% of the candidates taking the
test were girls so,

912=37.5% * Total # taking
test

So Total # taking the test =
912/(0.375)=2432

Since 37.5% of the candidates were girls
then 62.5% of the candidates were boys.

So Total # of boys
taking the test were 62.5%*2432 = 0.625(2432)=1520

Finally
since 75% of the boys passed the test, 25% failed so

25% of
1520 = 0.25*1520=380

So the answer is
380.