To find the marked price (M.P.) when the selling price (S.P.) is Rs 1600 and the discount is 20%, we use the following formula:

$\text{S.P.} = \text{M.P.} - (\text{Discount on M.P.})$

The discount is 20% of the marked price, so:

$\text{Discount} = \frac{20}{100} \times \text{M.P.} = 0.2 \times \text{M.P.}$

Thus, the selling price becomes:

$\text{S.P.} = \text{M.P.} - 0.2 \times \text{M.P.} = 0.8 \times \text{M.P.}$

Given that the selling price (S.P.) is Rs 1600, we can set up the equation:

$1600 = 0.8 \times \text{M.P.}$

Now, solve for the M.P.:

$\text{M.P.} = \frac{1600}{0.8} = 2000$

So, the marked price (M.P.) is Rs 2000.

Would you like more details on this? Here are some related questions to expand on:

1. How do you calculate the discount given a marked price and a discount percentage?
2. What is the formula to find the selling price if the marked price and discount rate are given?
3. How does increasing the discount percentage affect the selling price?
4. How do you calculate the profit or loss percentage based on selling and marked price?
5. What would be the marked price if the discount was 25% and the selling price was Rs 1600?

Tip: When dealing with percentages, always think of them as parts of 100 to make calculations easier.