UGC NET Questions (Paper – 1)

Let the original salaries be 7k and 9k. After adding ₹5600 to each, the new salaries become 7k + 5600 and 9k + 5600, which are in the ratio 9:11. So (7k + 5600)/(9k + 5600) = 9/11. Solving this equation gives k = 2800, so B’s original salary is 9k = 9 × 2800 = ₹25,200. Thus, ₹25,200 is the unique value that satisfies both the original and changed ratios.

Option A:
Option A, ₹19,600, equals 7 × 2800 and represents A’s original salary, not B’s. If we treat ₹19,600 as B’s original salary, we cannot express A’s salary as a smaller value in the ratio 7:9 while still matching the increment condition. Therefore it does not satisfy the relationship implied by the change from 7:9 to 9:11.

Option B:
Option B is correct because it matches the 9k term obtained from solving the proportion equation. Substituting ₹25,200 for B and ₹19,600 for A, we get new salaries ₹25,200 + ₹5600 = ₹30,800 and ₹19,600 + ₹5600 = ₹25,200, whose ratio is 25,200:30,800 = 9:11. This verifies that ₹25,200 is consistent with all given information.

Option C:
Option C, ₹28,000, would imply k = 3111.11… if we forced 9k = ₹28,000, which is not an integer and contradicts the natural-number scaling in the original ratio 7:9. Using that figure in the increment equation will not yield the new ratio 9:11. Hence, ₹28,000 cannot be B’s original salary.

Option D:
Option D, ₹30,800, is actually B’s new salary after the increment in the correct solution. Treating it as the original salary would lead to an even larger value after adding ₹5600 and a ratio that no longer matches 9:11. Therefore, ₹30,800 is not consistent with the given conditions.