Question

The price of an antique book is $91,which is two-fifth more then the cost to the book dealer.Find the cost.

Answer 1

The cost to book dealer is $65

Explanation:

Given : The price of an antique book is $91.

The price is two - fifth more than the cost to book dealer.

To Find : Cost.

Solution :

Let the cost to book dealer be x

The price of an antique book is $91.

Two - fifth of the dealer cost :
`(2)/(5)x`

Since we are given that price is two - fifth more than the cost to book dealer.

⇒
`x+(2)/(5)x=91`

⇒
`(7)/(5)x=91`

⇒
`x=(91*5)/(7)`

⇒
`x=(455)/(7)`

⇒
`x=65`

Hence , The cost to book dealer is $65

Answer 2

Let the price of book x. That's the cost the book dealer.

He wants to earn some money while selling it, so he listed the book by a new price, 91 $

He added two-fifth (2/5) price to its initial price. In other words, its new price is 40 % more expensive. (2/5 = x /100)

Here is the equation in words,
initial price + 2/5 of the initial price = 91

by equation: x + 2/5 x =91

multiply both sides by 5, to eliminate the denominator:

5x +2x = 91.5 ; 7x = 455

divide both sides by 7 to simply coefficient of x: x= 65

The answer is 65$.