Question

•After a discount of 30% on a book, Karan bought it for ₹ 84. What was the original price of the book?

•₹ 90

•₹ 115

•₹ 120

•₹ 135

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Answer 1

Question :

After a discount of 30% on a book, Karan bought it for ₹ 84. What was the original price of the book .

Answer :

$\sf\pink{Given}$

• Discount % is 30%

• Karan bought it for ₹ 84.

$\sf\pink{To\:Find}$

• Original price = ?

Explanation :

• let the original price be "x"

Discount % =${\dfrac{discount}{original\:price}\times 100}$

$\sf\purple{discount = original\:price - selling\:price}$

Discount % =${\dfrac{original\:price - selling\:price }{original\:price}\times 100}$

$\longrightarrow\sf{30 = \dfrac{x - 84}{x}\times 100}$

$\longrightarrow\sf{30= \dfrac{100x - 8400}{x}}$

$\longrightarrow\sf{30x = 100x - 8400}$

$\longrightarrow\sf{30x + 8400 = 100x }$

$\longrightarrow\sf{ 8400 = 100x - 30x }$

$\longrightarrow\sf{ 8400 = 70x }$

$\longrightarrow\sf{ x = \dfrac{8400}{70} }$

$\longrightarrow\sf{ x = \dfrac{840}{7} }$

$\longrightarrow\sf{ x = 120 }$

• Therefore its original price is ₹ 120 .