Mako? The marked price of a watch is 30% above the cost price. When it is sold allowing
20% discount on it, there is a gain of Rs 150. Find the marked price and the cost
price of the watch.
CO
When

The marked price of the watch is Rs 4875 and the cost price is Rs 3750

Explanation:

Let the cost price of the watch be Rs. y and the marked price of the watch be Rs. x.

The marked price of a watch is 30% above the cost price, therefore the marked price of the watch (x) = y + 30% × y = y + 0.3y = 1.3y.  

The watch is sold at 20% discount, this means it is sold at x - 20% × x = x - 0.2x = 0.8x.

When sold at 20% discount, there is a gain of Rs 150. Therefore:

0.8x = 150 + cost price

0.8x = 150 + y

but x = 1.3y

0.8(1.3y) = 150 + y

1.04y = 150 + y

1.04y - y = 150

0.04y = 150

y = 3750

Since x = 1.3y = 1.3(3750) = 4875

Therefore the marked price of the watch is Rs 4875 and the cost price is Rs 3750