List of top General Aptitude Questions on Ratio and Proportion asked in GATE CE, GATE XL

Both the numerator and the denominator of \( \frac{3}{4} \) are increased by a positive integer, \( x \), and those of \( \frac{15}{17} \) are decreased by the same integer. This operation results in the same value for both the fractions. What is the value of \( x \)?
If \( x : y : z = \frac{1}{2} : \frac{1}{3} : \frac{1}{4} \), what is the value of \( \frac{x + z - y}{y} \)?
The number of students in three classes is in the ratio \(3:13:6\). If 18 students are added to each class, the ratio changes to \(15:35:21\).
The total number of students in all the three classes in the beginning was: