Mohan had bought certain number of books for rupees 48.If he had bought 4 more for the same amount, then the cost of each book would have been reduced by 1 rupee.Find the number of books bought by him.
Answers
Answer:
So Mohan bought 16 books
Step-by-step explanation:
Let Mohan bought x books for rs 80
So the cost of each book was 80/x
If the cost of each books were re 1 less then he can buy 4 more books
So, he can buy x+4 books
So the cost of each of the book would be
80/(x+4)
According to the question,
80/x-80/(x+4)=1
(80x+320-80x)/(x^2 +4x)=1
x^2+4x=320
x^2+4x-320=0
x^2+20x-16x-320=0
x(x+20)-16(x+20)=0
(x+20)(x-16)=0
Therefore, x= -20, 16
As x wouldn't be negative because quantity of book cant be negative so x=16
So Mohan bought 16 books
Answer:
let the books brought by Mohan be x
cost of each books is 48/X
if he had brought 4 more books
therefore the cost of each book is 48 / X + 4
according according to the question
48/ X - 48/ X + 4= 1
48(X+4)-48x/X(X+4)=1
48x+192-48x=x^2+4x
x^2+4x-192=0
x^2+16x-12x-192=0
X(X+16)-12(X+16)=0
(X+16)(x-12)=0
X=-16 &X=12
ignoring the negative value
therefore number of books bought by him is 12..
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