Q29 of 180 Page 1

A bookseller buys a number of books for ₹ 1760. If he had bought 4 more books for the same amount, each book would have cost ₹ 22 less. How many books did he buy?

OR


A two-digit number is such that product of its digits is 18. When 63 is subtracted from the number, the digits interchange their places. Find the number.


Let the number of books bought initially is y.

Let the cost of each book bought initially is Rs x.


Initial condition,


⇒


Final condition,


⇒


Subtracting above two equations, we get


⇒


⇒


⇒


⇒


⇒


⇒


⇒


Number of books can’t be negative.


Hence, number of books = 16.


OR


Let the one’s place digit is y and digit at ten’s place is x.


It is given that,


The number can also be represented as,


⇒


⇒


⇒


Substituting in this equation.


⇒


⇒


⇒ ⇒


⇒


⇒


The value of y can’t be negative. So, y = 2 and x = 9


The required number is 92.


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