The price of a pen is 9 more than the price of a pencil.The price of a book is 8 rupees more that the price of a pen.Total price of 12 pens and 12 pencils is equal to the total price of 9 books.Find price of a pencil pen and a book.
Answers
Answer: Price of a pencil =3 rupees
Price of a pen=12 rupees
Price of a book=20 rupees
Solution:- Let the price of a pencil be x rupees then
the price of 12 pencils = 12x
the price of a pen = x+9 .....(1)
⇒ price of 12 pens = 12(x+9)
the price of a book = 8+x+9=x+17
⇒price of 9 books =9(x+17)......(2)
Now , the total price of 12 pens and 12 pencils (i.e. sum of price of 12 pens and 12 pencils ) =12(x+9)+12x=price of 9 books
⇒12(x+9)+12x=9(x+17)
⇒12x+108+12x=9x+153
⇒24x+108=9x+153(combining like terms)
⇒24x-9x=153-108 (subtracting 9x and 108 on both the sides)
⇒15x=45
⇒x=3 (dividing both sides by 15)
∴ Price of a pencil =x=3 rupees
∴Price of a pen=x+9=3+9=12 rupees (by putting the value of x in 1)
∴Price of a book=x+17=3+17=20 rupees (by putting the value of x in 2)