Advertisements
Advertisements
प्रश्न
If the price of a book is reduced by ₹ 5, a person can buy 4 more books for ₹ 600. Find the original price of the book.
उत्तर
Let the original price of the book be ₹ x.
∴ Number of books bought at original price for ₹ `600=600/x`
If the price of a book is reduced by ₹ 5, then the new price of the book is ₹ (x-5)
∴ Number of books bought at reduced price for ₹ `600=600/(x-5)`
According to the given condition,
`600/(x-5)-600/x=4`
⇒ `(600x-600x+3000)/(x(x-5))=4`
⇒ `3000/(x^2-5x)=750`
⇒`x^2-5x=750`
⇒`x^2-5x-750=0`
⇒`x^2-30x+25x-750=0`
⇒`x(x-30)+25(x-30)=0`
⇒`x-30=0 or x+25=0`
⇒`x=30 or x=-25`
∴ x=30 (Price cannot be negative)
Hence, the original price of the book is ₹30.
APPEARS IN
संबंधित प्रश्न
A man buys a number of pens for ₹ 180. If he had bought 3 more pens for the same amount, each pen would have cost him ₹ 3 less. How many pens did he buy?
The product of Tanvy’s age (in years) 5 years ago and her age is 8 years later is 30. Find her present age.
A truck covers a distance of 150 km at a certain average speed and then covers another 200 km at an average speed which is 20 km per hour more than the first speed. If the truck covers the total distance in 5 hours, find the first speed of the truck.
Two pipes running together can fill a cistern in `3 1/13`
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.
The length of a hall is 3 meter more than its breadth. If the area of the hall is 238 sq meters, calculate its length and breadth.
In a flight of 2800 km, an aircraft was slowed down due to bad weather. Its average speed is reduced by 100 km/h and time increased by 30 minutes. Find the original duration of the flight.
While boarding an aeroplane, a passenger got hurt. The pilot showing promptness and concern, made arrangements to hospitalise the injured and so the plane started late by 30 minutes to reach the destination, 1500 km away in time, the pilot increased the speed by 100 km/hr. Find the original speed/hour of the plane.
Write a quadratic polynomial, sum of whose zeros is \[2\sqrt{3}\] and their product is 2.
Raj and Ajay are very close friends. Both the families decide to go to Ranikhet by their own cars. Raj’s car travels at a speed of x km/h while Ajay’s car travels 5 km/h faster than Raj’s car. Raj took 4 hours more than Ajay to complete the journey of 400 km.
How much time took Ajay to travel 400 km?
The speed of a motorboat is 20 km/hr. For covering the distance of 15 km the boat took 1 hour more upstream than downstream.
Which is the correct quadratic equation for the speed of the current?
