Question

80% of 40 students are good in Mathematics. How many students are not good in mathematics?​

Answer 1

${ \underline{ \boxed{ \bf{ \red{SOLUTION :}}}}}$

Given

• Total students = 40
• Percentage of students good in maths = 80%

Percentage of students not good in maths = 100% - 80%

Percentage of students not good in maths = 20%

Finding number of students not good in maths

Let the number of students not good in maths = x

${ \mathsf{Percentage = \frac{number \: of \: students \: not \: good \: in \: maths}{Total \: students} \times 100}}$

${ \mathsf{20 = \frac{x}{40} \times 100}}$

${ \mathsf{20 = x \: \times 2.5}}$

${ \mathsf{ \frac{20}{2.5} = x}}$

${ \mathsf{8 = \: x}}$

${ \boxed{ \mathsf{ \purple{x \: = 8}}}} \star$

${\therefore{ \mathsf{ \underline{ \: 8 \: Students \: are \: not \: good \: in \: maths}}}}$

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