a shopkeeper bought two watches for rs 400. he sold them to gain 5% profit on one and another at 5% loss on other. calculate his final loss or profit percent. if the sp of both watches are same

0.25 % loss.

Step-by-step explanation:

Let the cost of 1 watch be rs x then the cost of the other is rs 400 - x.

Let the sp be rs y.

So we have:

y = x + 0.05x

y = (400 - x) - 0.05 (400 - x)

y = 400 - x - 20 + 0.05x

y = 380 - 0.95x

So x + 0.05x = 380 - 0.95x

2x = 380

x = 190.

and y = 190 + 0.05*190 = 199.5.

So the total selling price = 2 * 199.5 = rs 399

So final loss is [ (400-399) / 400] * 100

= 0.25 %.