Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 18 Dec 2013, 14:06

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# The number A is a two-digit positive integer; the number B

Author Message
TAGS:
Manager
Joined: 08 Sep 2010
Posts: 58
Followers: 0

Kudos [?]: 7 [0], given: 4

The number A is a two-digit positive integer; the number B [#permalink]  22 Jul 2011, 08:18
00:00

Difficulty:

5% (low)

Question Stats:

66% (01:49) correct 33% (00:31) wrong based on 9 sessions
The number A is a two-digit positive integer; the number B is the two-digit positive integer formed by reversing the digits of A. if Q=10B-A, what is the value of Q?

(1) The tens digit of A is 7
(2) The tens digit of B is 6

I am able to get the value of Q using (1) which is contrary to the provided answer.

(1)
A = 7/10 + x
B = x/10 + 7

Q=10B-A
Q=10(x/10 + 7) - (7/10 + x)
Q= x + 70 - 7/10 - x
Q= 10x + 700 - 7 - 10x
Q= 700 - 7
Q= 693

Does this mean that the answer provided by Manhattan is wrong?
[Reveal] Spoiler: OA

_________________

Don't forget to give me ****KUDOS****

Senior Manager
Joined: 03 Mar 2010
Posts: 447
Followers: 3

Kudos [?]: 90 [0], given: 21

Re: unknown digits [#permalink]  22 Jul 2011, 09:09
A=10x+y
B=10y+x
10B-A=10[10y+x]-10x-y=100y+10x-10x-y=99y

Stmt1: The tens digit of A is 7 i.e 10x=7. But we don't know Y. Insufficient.

Stmt2: The tens digit of B is 6 i.e 10y=6 y=0.6
Q=99y=99*0.6=59.4 Sufficient.

OA B
_________________

My dad once said to me: Son, nothing succeeds like success.

Re: unknown digits   [#permalink] 22 Jul 2011, 09:09
Similar topics Replies Last post
Similar
Topics:
If a and b are the digits of the two-digit number X, what is 3 01 Dec 2007, 20:56
If the sum of the digits of the positive two-digit number x 2 07 Mar 2009, 14:31
If a and b are two-digit numbers that share the same digits, 10 25 May 2010, 05:47
If the sum of the digits of the positive two-digit number x 6 31 Jan 2012, 17:15
2 If the two-digit integers A and B are positive and have the 3 18 Nov 2013, 11:19
Display posts from previous: Sort by