Cost price: $80

Selling price: $125

The price at which the watch was bought is the cost price. The price at which the watch was sold is the selling price. The selling price is more than the cost price, so the watch was sold at a profit or gain.

To calculate the dollar value of the profit or gain = Selling price (S.P) – Cost price (C.P)

= $125 – $80 = $45

To calculate the Percentage of the profit or gain = Gain/C.P x 100

=45/80 x 100 = 60%

Also….

Cost price: $250

Selling price: $210

The price at which the scooter was bought is the cost price. The price at which the scooter was sold is the selling price. The selling price is less than the cost price, so the scooter was sold at a loss.

To calculate the dollar value of the loss = C.P – S.P

Loss = $250 – $210 = $40

Loss % = 40/250 x 100 = 16%