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. |
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 3 of 3.
Abirami said:
2 years ago
Can anyone explain the second statement, how do we get 9? Please explain to me.
Sumanth Nakirikanti said:
1 year ago
If both options A and C are correct why would you mark option E.
Shayantan Kabiraj said:
11 months ago
D is the correct answer.
Because with only I and II, both 34 and 43 are possible answers.
With only I and III, 43, 52, 61 and 70, all are correct.
Only with I, II and III do we get a single answer, and that is 43.
Because with only I and II, both 34 and 43 are possible answers.
With only I and III, 43, 52, 61 and 70, all are correct.
Only with I, II and III do we get a single answer, and that is 43.
Mithra said:
5 months ago
Let the digits be xy.
x + y = 7,
x + x + 1 = 7
x = 3
y = 4
On interchanging 43-34 = 9.
Then option 1 and 3 are helpful,
Thus option C.
x + y = 7,
x + x + 1 = 7
x = 3
y = 4
On interchanging 43-34 = 9.
Then option 1 and 3 are helpful,
Thus option C.
Anbumani said:
3 months ago
I. x + y = 7.
III. x - y = 1.
By Adding I and III,
Then 2x = 8 => x = 4,
And y = 3.
III. x - y = 1.
By Adding I and III,
Then 2x = 8 => x = 4,
And y = 3.
Laxmi said:
1 month ago
But by statement 2 we can't decide which is larger right (xy or yx).
So, I think the answer should be I and III only.
So, I think the answer should be I and III only.
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