Aptitude - Problems on Numbers - Discussion

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"To err is human; to forgive, divine."

- Alexander Pope

Directions to Solve

Each of the questions given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statement(s) is/are necessary to answer the question.

What is the two-digit number?
I.
Sum of the digits is 7.
II.
Difference between the number and the number obtained by interchanging the digits is 9.
III.
Digit in the ten's place is bigger than the digit in the unit's place by 1.

[A].	I and II only	[B].	II and III only
[C].	I and III only	[D].	All I, II and III
[E].	None of these

Answer: Option D

Explanation:

Let the tens and units digit be x and y respectively.

I. x + y = 7.

II. (10x + y) - (10y + x) = 9 x - y = 1.

III. x - y = 1.

Thus, I and II as well as I and III give the answer.

Correct answer is (E).

Anurag said: (Fri, Dec 10, 2010 08:51:57 AM)

I think option (c) or even (a) is correct because I'm getting just "43" as answer.

Shekhar said: (Thu, Jun 23, 2011 12:47:23 AM)

correct answer is C) coz I gives x+y = 7. II gives mod i.e. \|(10x+y)-(x+10y)\| = 9 implying \|x-y\| = 1 or (x-y) = + or - 1 so number can only be either 34 or 43. So I and II together can't give answer.. But III gives Digit in the ten's place is bigger than the digit in the unit's place by 1. so fixing the no. as 43 using I and III.

Kushagra Jhamar said: (Fri, Sep 16, 2011 06:30:48 PM)

I think correct answer is D. As Shekar told answer is C that is can be answered using I and III, but we came to the conclusion (x-y)=1 by using II statement, we have to utilize all the three statenet in order to reach a single solution. And from I and II we can't give answer because it can be 34 or 43 either.

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Aptitude - Problems on Numbers - Discussion

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