Question

Sanvi purchased some books for rupees 120 if you purchased 3 more books for the same amount each book would have cost rupees 2 less .Find the number of books purchase by Saanvi and the price of each book.​

Answer 1

Answer:

Step-by-step explanation:

c= cost per book

n= number of books

Given: Total cost of books=120 rupees

i.e. (c) x (n) = 120 ...(1)

also, if 3 books extra and cost per book is 2 rupees less, then

(c-3) x (n-2) = 120

or cn + 6 -3n -2c = 120

or 120 + 6 -3n -2c =120         [From (1), cn=120]

or 6 = 3n-2c

or 2c = 3n -6

or c=(3n-6)/2

Substituting in eq(1)

(n)(3n-6)/2 = 120

or 3(n-2)(n)/2=120         [Taking 3 common]

or (n-2)(n)= (120 x 2)/3

or n^2 - 2n = 80

or n^2 - 2n -80 =0

or (n-10)(n+8)=0

or n = 10 or (-8)

but n cant be negative

hence number of books purchased is n=10

and cost of each book is c=120/n=120/10=12