The number of students in three sections of Grade 10 in a school are in the proportion 3 5 S If 15 3...........

Quantitative Aptitude (MTS) Ratio, Proportion

The number of students in three sections of Grade 10 in a school are in the proportion 3: 5 : S. If 15, 30 and 15 more students

are admitted in the three sections respectively, the new proportion becomes 4 : 7 : 9. The total number of students before the

new admissions is:

This questions was previously asked in

SSC MTS 18th October 2021 Shift-2

320

160

240

400

- Let's denote the initial numbers of students in the three sections as 3x, 5x, and Sx.

- After the addition of students, the new numbers are 3x + 15, 5x + 30, and Sx + 15.

- The new proportion is given by 4:7:9.

- Set up the new proportions:

\frac{3x + 15}{5x + 30} = \frac{4}{7}, \quad \frac{3x + 15}{Sx + 15} = \frac{4}{9}

- Solving these equations will give the values of x and S.

- Calculate the original total number of students by summing up 3x, 5x, and Sx.

The total number of students before the new admissions is indeed 240.

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