word problem

Asked by  | 23rd Feb, 2013, 03:49: PM

Expert Answer:

Let the price of each book by Rs x and the number of books bought be n
 
So, nx = 80
If he would have 4 more books, 
 
i.e. (n+4)(x-1)  = 80
Solving nx-n+4x-4 = 80
Substituing for x
80-n + 4*80/n - 4 = 80
n2 +4n - 320 = 0
n2 +20n-16n - 320 = 0
(n+20) (n-16) = 0
Since, n cant be negative, i..e n = 16. 
 
The person bought 16 books and price of each book was Rs 5. 

Answered by  | 23rd Feb, 2013, 06:44: PM

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