Correct option is (c) Rs 750
Let x be the profit that the seller makes on 5% discount.
Then, (x − 15) is the profit that he makes on 7% discount.
(100 − 5)% of M.P − (100 − 7)% of M.P = x − (x − 15) = 15
⇒ 2% of M.P = 15
⇒ M.P = \(15 \times \frac{100}2 = 750\)
∴ Marked Price is Rs.750.