Question
Sat February 23, 2013 By:

word problem

Expert Reply
Sat February 23, 2013
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
n+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. 
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