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Digits

Expert replies
Source: — Data Sufficiency |

Re: Digits

by Morgoth » Mon Sep 29, 2008 8:00 am
beater wrote:If the units digit of the three-digit positive integer k is nonzero, what is the tens digit of k?
(1) The tens digit of k + 9 is 3.
(2) The tens digit of k + 4 is 2.
IMO A

statement (1)

let k = xyz [3 digit, unit digit non zero]

x y z
++9
____
x30

minimum value of z can be 1 since it is non zero integer.
1+9 = 10
1 carry over to the tens y+1 = 3 , y =2

maximum value of z can be 9
9+9 = 18
1 carry over to the tens y+1 = 3 , y =2
Sufficient.

Statement (2)

x y z
++4
____
x2(z+4)

z=1, 1+4 = 5, y=2
z=9, 9+4 = 13, 1 carry over, if y=1, tens digit will be 2. Insufficient.

Thus, A.

OA?
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by beater » Mon Sep 29, 2008 5:23 pm
OA - A

Anyone with a different approach. Thanks!
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by beater » Mon Sep 29, 2008 5:49 pm
OA - A. Thanks!
Last edited by beater on Tue Sep 30, 2008 4:56 am, edited 1 time in total.
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by Morgoth » Tue Sep 30, 2008 2:13 am
What exactly is the OA, B or A?
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by beater » Tue Sep 30, 2008 4:56 am
Opps! Sorry for the mess. OA = A. Thanks!
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by gmatguy16 » Tue Sep 30, 2008 6:15 pm
can someone please explain how the oa is a,
if number =122 ,then 122+9 =131,tens digit is 3
if number =130, then 130+9=139 ,tens digit is 3 ,hence we have 2 different values of k ,2 and 3..did i mis u nderstood the question ?
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by Morgoth » Wed Oct 01, 2008 4:16 am
gmatguy16 wrote:can someone please explain how the oa is a,
if number =122 ,then 122+9 =131,tens digit is 3
if number =130, then 130+9=139 ,tens digit is 3 ,hence we have 2 different values of k ,2 and 3..did i mis u nderstood the question ?
Units digit of the number cannot be 0. Therefore minimum value of the units digit can be 1 and maximum value can be 9. Try with these two values, yu should get the answer.
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by gmattakers » Wed Oct 29, 2008 7:29 pm
The answer in the OA is A
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Re: Digits

by aj5105 » Fri Jan 02, 2009 6:29 pm
IMO A

BTW neat expl !
Morgoth wrote:
beater wrote:If the units digit of the three-digit positive integer k is nonzero, what is the tens digit of k?
(1) The tens digit of k + 9 is 3.
(2) The tens digit of k + 4 is 2.
IMO A

statement (1)

let k = xyz [3 digit, unit digit non zero]

x y z
++9
____
x30

minimum value of z can be 1 since it is non zero integer.
1+9 = 10
1 carry over to the tens y+1 = 3 , y =2

maximum value of z can be 9
9+9 = 18
1 carry over to the tens y+1 = 3 , y =2
Sufficient.

Statement (2)

x y z
++4
____
x2(z+4)

z=1, 1+4 = 5, y=2
z=9, 9+4 = 13, 1 carry over, if y=1, tens digit will be 2. Insufficient.

Thus, A.

OA?
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