Book: RS Aggarwal - Mathematics
Chapter: 10. Quadratic Equations
Subject: Maths - Class 10th
Q. No. 33 of Exercise 10E
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If the price of a book is reduced by Rs. 5, a person can buy 4 more books for Rs. 600. Find the original price of the book.
Let the original price of the book be Rs x
Number of books bought at original price for 600 = 
If the price of a book is reduced by Rs. 5, then new price of book is Rs (x – 5)
Number of books bought at reduced price = 
According to the question – –
x2 – 5x = 750
x2 – 5x – 750 = 0
Using the splitting middle term – the middle term of the general equation 
is divided in two such values that:
Product = a.c
For the given equation a = 1 b = – 5 c = – 750
= 1. – 750 = – 750
And either of their sum or difference = b
= – 5
Thus the two terms are – 30 and 25
Difference = – 30 + 25 = – 5
Product = – 30.25 = – 750
x2 – 5x – 750 = 0
x2 – 30x + 25x – 750 = 0
x(x – 30) + 25(x – 30) = 0
(x + 25) (x – 30) = 0
(x + 25) = 0 or (x – 30) = 0
x = – 25 , x = 30
x = 30 (Price cannot be negative)
Hence the original price of the book is Rs 30.
minutes. If one pipe takes 3 minutes more than the other to fill it, find the time in which each pipe would fill the cistern.
