Let the expense be ₹\(x\) and the number of residents be \(y\). Assume the total expense \(x = k_1 + B\), where \(k_1\) is the fixed part of the hostel expense and the remaining part \(B ∝ y\). So, \(B = k_2 y\), where \(k_2\) is a non-zero constant. Given: When \(y = 120\), \(x = 2000\) ⇒ \(2000 = k_1 + 120k_2\) — (I) When \(y = 100\), \(x = 1700\) ⇒ \(1700 = k_1 + 100k_2\) — (II) Subtracting (II) from (I): \(300 = 20k_2\) ⇒ \(k_2 = 15\) Substituting \(k_2 = 15\) into equation (I): \(2000 = k_1 + 120 × 15\) ⇒ \(k_1 = 2000 - 1800 = 200\) So, the expense equation becomes: \(x = 200 + 15y\) — (III) Now, when \(x = 1880\), using equation (III): \(1880 = 200 + 15y\) ⇒ \(15y = 1680\) ⇒ \(y = \frac{1680}{15} = 112\) ∴ When the hostel expense is ₹1880, the number of residents is 112.