# Price of a Book

If the list price of a book is reduced by Rs. 5, then a person can buy 5 more books for Rs. 300. The original cost of the book is
(1) Rs. 15
(2) Rs. 20
(3) Rs. 25
(4) Rs. 30
This question is related to Dell Interview

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#### rakesh8014 Profile Answers by rakesh8014 Questions by rakesh8014

• Jul 5th, 2010

Let 'x' be the no of book that we buy with 5 rupee less from the original book price and we buy 5 more books with the rest money each costing original book price.

so the no of cases arises are

Case 1:
x(15-5)+5(15)=300
Solving this equation we get the value of x =22.5 (which is a fraction value)
so this case is not possible.

Case 2:
x(20-5)+5(20)=300
Solving this equation we get the value of x =13.33 (which is a fraction value)
so this case is not possible.

Case 3:
x(25-5)+5(25)=300
Solving this equation we get the value of x =8.75 (which is a fraction value)
so this case is not possible.

Case 4:
x(30-5)+5(30)=300
Here we get the value of x =6 (which can be possibly a no. of book, so the original price of the book is 30).

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#### rivagupta Profile Answers by rivagupta

• Feb 16th, 2011

Let x be the list price
and y be the number of books
Then you can find x by the following 2 equations:
xy=300
(x-5)(y+5)=300

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#### Dennis

• Feb 10th, 2012

70Rs
let the original price of the book be x
let the original no. of books be y
that means x-5=y+5 which is the same as x+y=5+5
=x-y=10, x=10+y
but y+5=300Rs which is equals to 5y=300, y=60
since x=10+y but y=60, then x =70

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#### Manisha

• Dec 18th, 2013

Ans is (2) 20, simple to prove is 300/20(original price)-300/15(Rs reduce price)= Difference of total 5 books.
You can also solve below equation to get the result.

5+300/(x-5)=300/x
where x is the original price of the book, and left side of equation is after discount and right side is original.

I am sure this the correct answer

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#### FabianSterckx Profile Answers by FabianSterckx

• May 21st, 2014

(1): n.x <= 300
(2): (n+5).(x-5) <= 300

(1&2): (x-20).(x+15)=0

so x=20;
15 books at rs. 20 is 300
20 books at rs. 15 is 300

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#### JEBA SINGH.S

• Jun 5th, 2015

(4) Rs. 30

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#### Rahul

• Jun 7th, 2015

20

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#### Akshay Shah

• Jul 14th, 2016

Consider option 1
Rs.15
List Price is Rs.15
How many books were purchased at list price of 15 for Rs 300?
15x20=300
20 books.
if Rs.5 were reduced, now cost price is 10
then 20 Books were sold at 10x20=Rs 200
5 more books purchased at 10x5=Rs.50
Total amount now is 250 which is less than 300
Option 1) is Wrong.
similarly consider Option 2)20.
List Price=Rs.20
20x15=Rs.300(15 books for Rs 20 each)
20-5=15.(Rs 5 reduced From list price)
15x15=Rs.225
15x5=Rs.75
Total=Rs 300
Option 2) 20 is Correct
overall Funda :P
1)divide option with 300(Overall Cost) to find total number of books purchased at List price .(let number of books )
2)(List Price - 5)* no of books=x.
3)(list pric-5)*5 =y.
4)if x+y=300. option is correct!

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