Question

in a school 4/7 of the student are boys if there are 210 girls, find the number of boys in the school.

Answer 1

Answer:

Number of boys = 280

Step-by-step explanation:

Let Total number of students in a school = x

$i) Number\: of \:boys<strong> </strong>= \frac{4}{7}\: of\: x\\=\frac{4x}{7}$

ii) Number of girls = 210

\* given *\

$\implies x-\frac{4x}{7}=210$

$\implies \frac{7x-4x}{7}=210$

$\implies \frac{3x}{7}=210$

$\implies x = \frac{210 \times 7}{3}$

$\implies x =70 \times 7$

$\implies x = 490$

Therefore,

Total number of students in a school = x = 490

Number of boys = x - number of girls

= 490 - 210

= 280

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Answer 2

Let Total number of students in a school = x

\begin{gathered}i) Number\: of \:boys = \frac{4}{7}\: of\: x\\=\frac{4x}{7}\end{gathered}

i)Numberofboys=

7

4

ofx

=

7

4x

ii) Number of girls = 210

\* given *\

\implies x-\frac{4x}{7}=210⟹x−

7

4x

=210

\implies \frac{7x-4x}{7}=210⟹

7

7x−4x

=210

\implies \frac{3x}{7}=210⟹

7

3x

=210

\implies x = \frac{210 \times 7}{3}⟹x=

3

210×7