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Re: Number Properties - DS [#permalink]
25 May 2010, 06:04

Expert's post

srichaks wrote:

Q:If a and b are two-digit numbers that share the same digits, except in reverse order, then what is the sum of a and b? (1) a-b=45 (2) The difference between the two digits in each number is 5.

Please explain your answer in detail including why each choice is right or wrong?

Re: Number Properties - DS [#permalink]
25 May 2010, 21:55

srichaks wrote:

Q:If a and b are two-digit numbers that share the same digits, except in reverse order, then what is the sum of a and b? (1) a-b=45 (2) The difference between the two digits in each number is 5.

Please explain your answer in detail including why each choice is right or wrong?

Re: Number Properties - DS [#permalink]
29 May 2010, 06:20

Expert's post

hardnstrong wrote:

I dont understand the "except in reverse order" part???????

It means that if digits in a are xy, then in b the digits are yx (in reverse order).

According to the solution above there are 5 pairs of a and b possible satisfying both statements (94 and 49, 83 and 38, 72 and 27, 61 and 16). So multiple answer to a+b. Not sufficient.

Re: Number Properties - DS [#permalink]
30 May 2010, 05:27

Bunuel wrote:

hardnstrong wrote:

I dont understand the "except in reverse order" part???????

It means that if digits in a are xy, then in b the digits are yx (in reverse order).

According to the solution above there are 5 pairs of a and b possible satisfying both statements (94 and 49, 83 and 38, 72 and 27, 61 and 16). So multiple answer to a+b. Not sufficient.

Hope it's clear.

This is the confusing part in this question............ except in reverse order means they cannot be in reverse order (so if a = xy then b cannot be yx)

Dont you think "except in reverse order" takes question is completely different direction, or should it be "in reverse order" _________________

Re: Number Properties - DS [#permalink]
30 May 2010, 05:40

Expert's post

hardnstrong wrote:

Bunuel wrote:

hardnstrong wrote:

I dont understand the "except in reverse order" part???????

It means that if digits in a are xy, then in b the digits are yx (in reverse order).

According to the solution above there are 5 pairs of a and b possible satisfying both statements (94 and 49, 83 and 38, 72 and 27, 61 and 16). So multiple answer to a+b. Not sufficient.

Hope it's clear.

This is the confusing part in this question............ except in reverse order means they cannot be in reverse order (so if a = xy then b cannot be yx)

Dont you think "except in reverse order" takes question is completely different direction, or should it be "in reverse order"

Not a perfect wording - agree. "except in reverse order" here means "but in reverse order". _________________

Re: If a and b are two-digit numbers that share the same digits, [#permalink]
29 Jan 2014, 12:19

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Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________