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In the addition problem above, A and B represent digits in two differe

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Bunuel
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In the addition problem above, A and B represent digits in two differe [#permalink] New post   11 Dec 2015, 09:22
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A
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Difficulty:

5% (low)

Question Stats:

94% (01:04) correct 6% (02:16) wrong based on 146 sessions
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AB
+BA
___
121

In the addition problem above, A and B represent digits in two different two-digit numbers. What is the sum of A and B?

A. 6
B. 8
C. 9
D. 11
E. 14
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D
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Re: In the addition problem above, A and B represent digits in two differe [#permalink] New post   11 Dec 2015, 09:27
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Bunuel wrote:
AB
+BA
___
121

In the addition problem above, A and B represent digits in two different two-digit numbers. What is the sum of A and B?

A. 6
B. 8
C. 9
D. 11
E. 14


two ways to do it..

1) straight logic..
we can see that ones digit is 1 when units digit B and A are added..
answer has to be 1 in the units digit..
only 11 fits in..

2) BA=10B+A, and
AB=10A+B..
it is given that BA+AB=121..
or 10B+A +10A+B=121..
11(A+B)=121..
so A+B=11..
D
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Re: In the addition problem above, A and B represent digits in two differe [#permalink] New post   03 Sep 2020, 08:33
Expert Reply
Given

    • AB
    +BA
    ___
    121
    • A and B represent digits in two different two-digit numbers


To Find

    • The sum of A and B.

Approach and Working Out

    • AB = 10A + B and BA = 10B + A

    • AB + BA = 10A + B + 10B + A
      o 11 (A + B)

    • 11 (A + B) = 121
      o A + B = 11

Correct Answer: Option D
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Re: In the addition problem above, A and B represent digits in two differe [#permalink] New post   08 Sep 2020, 10:35
Expert Reply
Bunuel wrote:
AB
+BA
___
121

In the addition problem above, A and B represent digits in two different two-digit numbers. What is the sum of A and B?

A. 6
B. 8
C. 9
D. 11
E. 14

Solution:

Without loss of generality, we can let A > B. Thus the two-digit number AB can be 65, 74, 83 or 92. In any case, A + B = 11.

Alternate Solution:

We can re-express AB as 10A + B and similarly, we can re-express BA as 10B + A. Thus, we can say:

(10A + B) + (10B + A) = 121

11A + 11B = 121

A + B = 11

Answer: D
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Re: In the addition problem above, A and B represent digits in two differe [#permalink] New post   18 Jul 2023, 07:26
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Re: In the addition problem above, A and B represent digits in two differe [#permalink]
18 Jul 2023, 07:26
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