Aptitude - Problems on Numbers - Discussion

Discussion Forum : Problems on Numbers - Data Sufficiency 2 (Q.No. 2)
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.


2.

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.

I and II only
II and III only
I and III only
All I, II and III
None of these
Answer: Option
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).

Discussion:
26 comments Page 1 of 3.

Anurag said:   1 decade ago
I think option (c) or even (a) is correct because I'm getting just "43" as answer.

Shekhar said:   1 decade ago
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:   1 decade ago
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.

Swapnil said:   1 decade ago
The answer is D.

The first condition gives 6 numbers.

16, 25, 34, 43, 52, 61.

From 2nd statement we get 43 and 34.

From the 3rd statement we get 43.

Suraj Nambiar said:   1 decade ago
The Answer E is correct. This is because the answer can be obtained by A as well as B and not A (or B) alone as the option states.

Gaurav Goyal said:   1 decade ago
I believe E is correct.

Either we can obtain the answer from 1 & 3 or from 1, 2 and 3.

Arjun said:   1 decade ago
I think answer will be D for sure. There is no discussion in that.

Shweta said:   1 decade ago
The answer should be C x+y=7, x-y=1.

Ankit kaswa said:   1 decade ago
Correct answer will be C (I & III only) because II give information about difference, so using I & II we can gate 43 or 34.

Amit Mandliya said:   1 decade ago
C should be the answer. As I & III are providing required information.


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