A shopkeeper sold a wrist watch for ₹ 990 gaining 1 8 of its cost price. Find the cost price of the wrist watch and his profit percent.

S.P. of wrist watch = ₹ 990 Let the C.P. of wrist watch be x Then profit = 1 8 × x = x 8 Now, profit = S . P . - C . P . x 8 = 990 - x ⇒ x + x 8 = 990 Take LCM, ⇒ 8 x + x 8 = 990 ⇒ 9 x 8 = 990 ⇒ x = 110 × 8 = ₹ 880 % profit = 990 - 880 880 × 100 = 110 880 × 100 % profit = 100 8 = 12 . 5 %

A shopkeeper sold a wrist watch for ₹ 990 gaining 1 8 of its cost price. Find the cost price of the wrist watch and his profit percent.

S.P. of wrist watch = ₹ 990 Let the C.P. of wrist watch be x Then profit = 1 8 × x = x 8 Now, profit = S . P . - C . P . x 8 = 990 - x ⇒ x + x 8 = 990 Take LCM, ⇒ 8 x + x 8 = 990 ⇒ 9 x 8 = 990 ⇒ x = 110 × 8 = ₹ 880 % profit = 990 - 880 880 × 100 = 110 880 × 100 % profit = 100 8 = 12 . 5 %

If the selling price of a laptop is equal to 1 1 5 of its cost price, find the profit percent.

Let C.P. of laptop be x then S.P. of laptop = 1 1 5 x = 6 x 5 ⇒ profit = S . P . - C . P . = 6 x 5 - x = x 5 Now, % profit = x 5 x × 100 = 1 5 × 100 % profit = 20 %