|
Author |
Message |
|
TAGS:
|
|
|
Senior Manager
Joined: 22 Aug 2003
Posts: 262
Location: Bangalore
Followers: 1
Kudos [?]:
1
[0], given: 0
|
What is the units' digit of (76)^k ?" (1) k is a prime [#permalink]
 16 Nov 2003, 00:26
Question Stats:
0% (00:00) correct
 0% (00:00) wrong based on 0 sessions
"What is the units' digit of (76)^k ?"
(1) k is a prime integer
(2) k is greater than 2.
please explain your solution. That's the only way to understand the question 
|
|
|
|
|
|
|
Manager
Joined: 26 Aug 2003
Posts: 238
Location: United States
Followers: 1
Kudos [?]:
1
[0], given: 0
|
I vote for A.
Since every integer power of 6 results in 6 as the unit digit, it sufficient to know that k is an integer. Whereas Statement (2) doesn't tell us anything about what kind of number k is.
|
|
|
|
|
|
Intern
Joined: 10 Oct 2003
Posts: 46
Location: Finland
Followers: 1
Kudos [?]:
0
[0], given: 0
|
I go with A too. The only case where the units digit is not 6 would be when k is 0 or k is a fraction.
|
|
|
|
|
|
Senior Manager
Joined: 22 Aug 2003
Posts: 262
Location: Bangalore
Followers: 1
Kudos [?]:
1
[0], given: 0
|
correct.
i was right in disagreeing with the official answer which was D.
thanks
|
|
|
|
|
|
Director
Joined: 13 Nov 2003
Posts: 811
Location: BULGARIA
Followers: 1
Kudos [?]:
6
[0], given: 0
|
Hallo Vicky think that the answer is correct, no matter what K is the units digit will always be 6...think makes sense  P.S: In every case you have 6 multiplied by 6 which is ultimately 6( in units place) no matter what the power is
|
|
|
|
|
|
Intern
Joined: 11 Nov 2003
Posts: 34
Location: CA
Followers: 1
Kudos [?]:
0
[0], given: 0
|
I agree with BG.
I think asnwer is D
|
|
|
|
|
|
VP
Joined: 13 Nov 2003
Posts: 1031
Location: Florida
Followers: 1
Kudos [?]:
5
[0], given: 0
|
whatever the power be, the unit digit will be "6". so it's D
|
|
|
|
|
|
Senior Manager
Joined: 30 Aug 2003
Posts: 348
Location: dallas , tx
Followers: 1
Kudos [?]:
2
[0], given: 0
|
How can it be A .. coz it states that k is prime ..but 6 is not a prime number....D is right..
_________________
shubhangi
|
|
|
|
|
|
Senior Manager
Joined: 22 Aug 2003
Posts: 262
Location: Bangalore
Followers: 1
Kudos [?]:
1
[0], given: 0
|
dear freinds.. u have missed one major pioint.
statement 1)
K is a prime number.
Thus whatever be the value of k =2,3,5...
Units digit of (76)^k will always be 6.
Satement 2)
K > 2 . If it was given that k is integer also, then definitely stat. 2 is also suffecient.
what if k = 2.5, 3.5 or any other fraction...!!
Thus 2 is not suffecient.
Hence Ans - A.
ps: Please be cautious in DS questions that involves variables x, y or k.
Check 1: Note down the domain of these variables - positive, negative, or just real numbers.
Check 2: Be sure to check each statement 1 & 2 for all possible values of these variables x, y within the above domain: positive, negative, fractions, underroots, etc...
thx
|
|
|
|
|
|
Manager
Joined: 26 Aug 2003
Posts: 238
Location: United States
Followers: 1
Kudos [?]:
1
[0], given: 0
|
Hey Vicky,
Where did you find this problem? I hope it's not OG because this would show a major flaw on the ETS' part.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Similar topics |
Author |
Replies |
Last post |
|
Similar
Topics:
|
 |
|
|
1) What is the units digit of 9^231? 2) What is units digit
|
jjomalls |
3 |
19 May 2004, 11:09 |
 |
|
|
A three-digit number k, the units digit is non-zero, what is
|
rahulraao |
17 |
05 Oct 2005, 03:03 |
|
|
|
|
A three-digit number k, the units digit is non-zero, what is
|
sudhagar |
9 |
11 Oct 2005, 09:37 |
|
|
|
|
IF K/60125 = 0.001, what is the unit digit of K? A) 0
|
TOUGH GUY |
1 |
27 Nov 2005, 07:44 |
|
|
4
|
|
What is the units digit of integer s? (1) The units digit of
|
dreambeliever |
16 |
07 Jun 2011, 08:05 |
|
|
|
|
|
|
close
