(solved)Question 1 SSC-CGL 2020 March 4 Shift 2

The ratio of boys and girls in a class is 7:6. When 4 new boys joined the class, 3 girls left it and the ratio of boys and girls becomes 4:3. Find the number of total students that were in the class initially.

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Question 1SSC-CGL 2020 Mar 4 Shift 2

The ratio of boys and girls in a class is 7:6. When 4 new boys joined the class, 3 girls left it and the ratio of boys and girls becomes 4:3. Find the number of total students that were in the class initially.

Solution in Detail

Initially, boys = $\displaystyle 7k$, girls = $\displaystyle 6k$

When 4 boys join, and 3 girls leave, the ratio becomes

$\displaystyle \frac{7k + 4}{6k - 3} = \frac{4}{3}$

Solving, $\displaystyle k = 8$

Total students initially $\displaystyle = 7k + 6k$

$\displaystyle = 13k = 13 \times 8 = 104\:\underline{Ans}$