Question

$72\%$ of $25$ students are good in mathematics. How many are not good in mathematics?

Answer 1

Given: $72\%$ of $25$ students are good in mathematics

$\Rightarrow$ Percentage of students good in Mathematics $+$ Percentage of students not good in Mathematics $=100\%$

$\Rightarrow$ Percentage of students not good in Mathematics
$=100\%-72\%=28\%$

No. of students not good in Mathematics $=28\%\text{of}25=\frac{28}{100}\times 25=7$

Hence, $7$ students are not good in Mathematics.