Quantitative Aptitude Ques 1937

Question: The difference between a two-digit number and the number obtained by interchanging the two digits of the number is 9. What is the difference between the two digits of the number? [IBPS (PO) 2011]

Options:

A) 3

B) 2

C) 1

D) 4

E) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

  • Let the number be $ 10x+y. $ The number by interchanging the position of the digit $ =10y+x $ Now, $ (10x+y)-(10y+x)=9 $

$ \Rightarrow $ $ 9x-9y=9 $

$ \Rightarrow $ $ 9(x-y)=9 $
$ \Rightarrow $ $ (x-y)=1 $