Aptitude - Problems on Numbers - Discussion

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"Everyone is wise until he speaks."

- (Proverb)

The sum of the digits of a two-digit number is 15 and the difference between the digits is 3. What is the two-digit number?

Answer: Option B

Explanation:

Let the ten's digit be x and unit's digit be y.

Then, x + y = 15 and x - y = 3 or y - x = 3.

Solving x + y = 15 and x - y = 3, we get: x = 9, y = 6.

Solving x + y = 15 and y - x = 3, we get: x = 6, y = 9.

So, the number is either 96 or 69.

Hence, the number cannot be determined.

Dominic said: (Fri, Jul 29, 2011 03:32:42 PM)

If we take 69 as answer. Sum becomes:6+9=15. But difference become: 6-9=-3. But from the question, the sum should be 15 and the difference 3, not -3. On this note, I strongly believe that, the correct answer is 96, because. Sum: 9+6=15, And difference: 9-6=3.

Sundar said: (Wed, Jun 13, 2012 01:03:57 PM)

@Dominic You are wrong. The given answer is correct. I want to ask a question to you. Assume your height is 165 cm and your friend's height is 170 cm. Now tell me what is the height-difference between you and your friend? Is it 5 cm or -5cm ? We usually write difference between x and y as X ~ Y NOT as X - Y. Hence the given answer 'Cannot be determined' is correct.

Moola V Reddy said: (Tue, Jun 26, 2012 07:12:08 AM)

I agree with Dominic always read the question carefully 1.sum of the two digits 2.difference between them sundar said good example of difference but there is no sum

Sally said: (Sun, Mar 10, 2013 11:56:38 PM)

Could somebody explain why we are not taking the tens digit as 10x and the ones digit as y, Like it was done in the previous questions?