A shopkeeper buys a number of books for Rs 80.If he had bought 4 more books for the same amount ,each book would have costed Rs 1 less. How many books did he buy?
Answers
Answered by
5
let total no. of books = K
total money = 80£
Ac/ Q
80/K = 80/(K+4)+1
80/K = (80+K+4)/(K+4)
80(K+4) = K(84+k)
80K +320 = 84K + K^2
K^2 + 4K -320 = 0
K^2 + 20k - 16k - 320 = 0
(K- 16)(K+20) =0
K-16 = 0
K = 16£ Ans
total money = 80£
Ac/ Q
80/K = 80/(K+4)+1
80/K = (80+K+4)/(K+4)
80(K+4) = K(84+k)
80K +320 = 84K + K^2
K^2 + 4K -320 = 0
K^2 + 20k - 16k - 320 = 0
(K- 16)(K+20) =0
K-16 = 0
K = 16£ Ans
Answered by
1
Answer:
VarghesebijupbaxnsHelping Hand
Eq no 1:- total books purchased = x
Therefore unit price = 80/ x
Eq no 2:- 4 extra book purchased on same price = ×+4 =80
Therefore unit price = 80/(×+4)
Difference of price is Rs. 1
Hence 80/× - 80/(x-4) =1
By solving the equation
320/ (xpower2 + 4x)=0
Xpower2+4x-320=0
X(X+20) -16(X+20)=0
(X+20) (X-16)=0
X=-20, X=16
We negate negative answer
Therefore no of books brought =16
Similar questions