Last year, Geeta's monthly salary was ₹12,000 and Seeta's monthly salary was ₹10,000. This year, Geeta's monthly salary is ₹14,400, while Seeta's monthly salary is ₹12,500. If the percentage increase in Seeta's monthly salary this year over her monthly salary last year is denoted by x%, and the percentage increase in Geeta's monthly salary this year over her monthly salary last year is denoted by y%, then what is the value of \(\rm \left(\frac{x-y}{y}\times100\right)\)%? 

Given:

Geeta's last year monthly salary = ₹12,000

Seeta's last year monthly salary = ₹10,000

Geeta's this year monthly salary = ₹14,400

Seeta's this year monthly salary = ₹12,500

Formula used:

Percentage increase = \(\left(\frac{\text{New Salary} - \text{Old Salary}}{\text{Old Salary}}\right) \times 100\)

Required value = \(\left(\frac{x-y}{y}\times100\right)\)%

Calculations:

Seeta's percentage increase (x%):

⇒ x = \(\left(\frac{12500 - 10000}{10000}\right) \times 100\)

⇒ x = \(\left(\frac{2500}{10000}\right) \times 100\)

⇒ x = 25%

Geeta's percentage increase (y%):

⇒ y = \(\left(\frac{14400 - 12000}{12000}\right) \times 100\)

⇒ y = \(\left(\frac{2400}{12000}\right) \times 100\)

⇒ y = 20%

Required value:

⇒ \(\left(\frac{25 - 20}{20} \times 100\right)\)

⇒ \(\left(\frac{5}{20} \times 100\right)\)

⇒ 25%

∴ The correct answer is option (4).