Question

In the class boys are 4/7 if there are 18 girls. Find the total number of pupils and how many boys are there?

Answer 1

Let the number of boys in the class be represented as \( B \) and the number of girls be represented as \( G \). According to the problem, we are given that there are 18 girls, so \( G = 18 \).

We know that the ratio of boys to the total number of pupils (boys and girls) is given by:

\[
\frac{B}{B + G} = \frac{4}{7}
\]

Substituting \( G = 18 \) into the equation, we have:

\[
\frac{B}{B + 18} = \frac{4}{7}
\]

To eliminate the fraction, we can cross-multiply:

\[
7B = 4(B + 18)
\]

Expanding the right side:

\[
7B = 4B + 72
\]

Now, we isolate \( B \):

\[
7B - 4B = 72
\]

\[
3B = 72
\]

Dividing both sides by 3 gives:

\[
B = 24
\]

Now, we can find the total number of pupils:

\[
Total = B + G = 24 + 18 = 42
\]

Therefore, the total number of pupils is **42**, and the number of boys is **24**.