Question

The ratio of the number of boys and girls who participated in an examination is $4:3$. The total percentage of candidates who passed the examination is $80$ and the percentage of girls who passed is $90$. The percentage of boys who passed is ____.

• A. $72.50$
• B. $90.00$
• C. $80.50$
• D. $55.50$

Answer 1

The correct option is A $72.50$

Let Number of boys $=4x$
and Number of girls $=3x$
Total passed candidates
$=\frac{80}{100}\times 7x=\frac{28}{5}x$

Number of girls candidates who passed
$=\frac{90}{100}\times 3x=\frac{27}{10}x$

Now total number of candidates passed = Number of girls who passed + Number of boys who passed

$\Rightarrow$ Number of boys who passed

$=(\frac{28}{5}-\frac{27}{10})x=\frac{56-27}{10}x=\frac{29}{10}x$

$\%ofboys=\frac{29}{10\times 4x}x\times 100=72.5\%$