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by sochatte » Wed Nov 28, 2007 11:15 pm
Q26:
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.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
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Source: — Data Sufficiency |
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by camitava » Wed Nov 28, 2007 11:30 pm
sochatte, lets ten's digit = x
By stmt - 1, x + 9 = 3 -> This proves we are not taking care of tens digit of the summation. And x should be 4.
By stmt - 2, x + 4 = 2 -> Same thoery follows here also and x should be 8.
But here I am getting confused. Why two different results from two stmts. Though IMO D, but still having some doubt.
Correct me If I am wrong


Regards,

Amitava
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by syv11 » Wed Nov 28, 2007 11:45 pm
The way I understand it is

(1) The tens digit of k + 9 is 3.

abc
a hundred
b tens
c unit

c?

bc+9 = 3

bc can be 21, 22, 23, 24, 25, 26, 27, 28, 29, 30

Not enough to know what c is

(2) The tens digit of k + 4 is 2.

bc can be 16, 17, 18, 19, 20, 21, 22, 23, 24, 25

Not enough

Combined, still enough

What do you think?
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by sochatte » Thu Nov 29, 2007 12:43 am
hey guys thx for replying. However, the ans is A. But now I think I understand what is going on here.

1. basically stmt 1 says
the tens digit of k + 9 is 3 so when we do abc + 9, b becomes 3.
Since we know c is between 1 and 9, we can find b is 2.

2. The tens digit of k + 4 is 2.
this means we do abc + 4, b becomes 2. but here if c is below 6 we get b = 2 and for c> 6 , we get b = 1. so not suff.

QA is A
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by camitava » Thu Nov 29, 2007 12:45 am
syv11, agree with your approach! But I am not getting one thing -
The Qs is saying -
(1) The tens digit of k + 9 is 3.
(2) The tens digit of k + 4 is 2.
So we should only take tens digit of the number but not both the tens and unit digit.
Am I missing something? Or I have not still able to understand the Qs at all. Because by approach, we are not getting the same result from two diff stmt. But by approach, we are still not able to gather a concrete answer of the Qs.
Correct me If I am wrong


Regards,

Amitava
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by samirpandeyit62 » Thu Nov 29, 2007 1:04 am
If the units digit of the three-digit positive integer k is nonzero, what is the tens digit of k?

let the nos be abc so c<> 0 & ofcourse a <>0

(1) The tens digit of k + 9 is 3.

alos c is between 1 to 9

so if we add 9 to c we will always get a carry(1) which will get added to the 10's digit of k i.e b hence b=2

(2) The tens digit of k + 4 is 2.

here if c =6,7,8.. then k+4 will produce a carry so tens digit of k will be 1 i.e 1 less than k+4

also if c is a value like 1,2,3 etc then the tens digit of k+4 = tens digit of k as there would be no carry produced INSUFF

A
Regards
Samir
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