Question

kaveri bought some books for rs. 60. if she had bought 5 more books for same amount each book would have cost her 1 rs lee . find the no. of book bought by kaveri and the price of each book.

Answer 1

please mark it as a brainliest answer

Answer 2

Answer:  

Let the original number of books = x,

⇒ Total expenditure = 60 rupees,

⇒ The price of the each book  = $\frac{60}{x}$

Now, The new numbers of books = x+5

⇒ The new price of the book = $\frac{60}{x+5}$

According to the question,

$\frac{60}{x}=\frac{60}{x+5}+1$

⇒ $\frac{60}{x}=\frac{60+x+5}{x+5}$

⇒ $60(x+5) = 65x + x^2$

⇒ $60x + 300 = 65x + x^2$

⇒ $x^2+5x - 300=0$

⇒ $x^2 + 20x - 15x - 300=0$

⇒ $x(x+20)-15(x+20)=0$

⇒ $(x-15)(x+20)=0$

Thus, x = 15 or -20

But number of books can not be negative,

⇒ The original number of books = 15

And, the price of each book = 60/15 = 4 rupees.