Question

Out of $8000$ candidates, $60\%$ were boys. If $80\%$ of the boys and $90\%$ of the girls passed the exam, find the number of candidates who failed.

Answer 1

Total candidates $=8000$

Number of boys $800\times \frac{60}{100}=4800$

Number of girls $8000-4800=3200$

number of boys fail $4800\times \frac{20}{100}=960$ ($80\%$ passed)

Number of girls failed $3200\times \frac{10}{100}=320$

Total failed $=1280$