TCS
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Logical Reasoning
Cryptography
What is the remainder when 6^17+117^6 is divided by 7?
A. 1
B. 6
C. 0
D. 3
Read Solution (Total 9)
-
- 1)6^17 mod 7
(7-1)^17 mod 7
(-1)^17 mod 7
=-1
2)117^6 mod 7
(16*7+5)^6 mod 7
(5)^6 mod 7
(25)^3 mod 7
(7*3+4)^3 mod 7
(4)^3 mod 7
64 mod 7
=1
6^17+117^6 is divided by 7 will be (1)+(2)
-1+1=0
remainder when 6^17+117^6 is divided by 7 will be 0(ans)
C. 0 (ans) - 12 years agoHelpfull: Yes(51) No(1)
- (7-1)^17 + (119-2)^6
=7X-1 + 7Y+ 2^6 [x&y are constants]
=7(X+Y)+63
=7(X+Y+9)
so rem is 0 - 12 years agoHelpfull: Yes(11) No(2)
- the answer is 1.
6 to the power anything will always result ending with last digit at 6.
now consider the next part.. 117 to the power 6 .. assume it to be xx7 to the power 6 ie just focus on 7 and 6... 7 to the power can be broken as 49*49*49 .. this will rsult in something ending with 9...
now add the remainders of first and second part.. ie 6+9=15
15%7=1... thats so simple - 12 years agoHelpfull: Yes(5) No(15)
- consider unit digit power of this div by4 remainder of this is power of init digit so 6^1+7^2=55
55/7=remain6 - 12 years agoHelpfull: Yes(2) No(3)
- 6793/7=256 and rem=1
ans=1 - 12 years agoHelpfull: Yes(1) No(14)
- ans option may be B or C..
- 12 years agoHelpfull: Yes(1) No(3)
- yess..0 is d ans...got it..
- 12 years agoHelpfull: Yes(1) No(1)
- Solutoon is 0
- 9 years agoHelpfull: Yes(0) No(0)
- Solutoon is 0
- 9 years agoHelpfull: Yes(0) No(0)
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