A man buys a chair and table for Rs. 6000. He sells the chair at a loss of 10% and the table at gain of 10%. He still gains Rs. 100 on the whole. Cost price of chair is:

A. Rs. 2500 B. Rs. 2850 C. Rs. 3050 D. Rs. 3500 Answer: Option A
If the CP of the chair be Rs. x then, Total SP = $\frac{\mathrm{x} \times 90}{100}+\left((6000-\mathrm{x}) \times \frac{110}{100}\right)$ Or, 9x + 66000 – 11x = 61000 Or, 2x = 66000 – 61000 = 5000 Or, x = Rs. 2500