Compute the remainder when 4 9 6 is divided by 6 .
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4 9 6 ≡ 1 6 4 8 ( m o d 6 ) ≡ 4 4 8 ( m o d 6 )
≡ 1 6 2 4 ( m o d 6 ) ≡ 4 2 4 ( m o d 6 ) (and it repeats)
≡ 1 6 1 2 ( m o d 6 ) ≡ 1 6 6 ( m o d 6 ) ≡ 1 6 3 ( m o d 6 )
≡ 4 3 ( m o d 6 ) ≡ 6 4 ( m o d 6 ) ≡ 4 ( m o d 6 )
we can simply solve this by forming a series as
4 , 16 , 64 , 256 , 1024 , 4096 ...........................................................................................
in each of the case remainder is 4 hence it can be clearly concluded that the remainder is 4.
It's not a solution but... I guessed 4. It's 50% chance. Possible reminders of any division to 6 are 1,2,3,4,5. Reminders 1,3,5 impossible because of 4^96 is even number. So my guess is correct.
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Not a good method. You were lucky that you got it correct
In a free response question, you probably shouldn't do that. Besides, you should never eliminate the possibility of remainder being 0 unless it's pretty much certain you can prove.
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You can prove that the remainder isn't 0. This is because 4 9 6 isn't divisible by 6.
4 9 6 is divisible by 2, but not divisible by 3.
The sum of the digits of powers of 4 go up in the sequence 3 n + 1 , hence they are never divisible by 3.
Examples: Power of 4 (sum of digits), 4 (4), 16 (7), 64 (10), 256 (13), 1024 (10+2+4 = 16), 4096 (19), 16384 (22) ...
4 ≡ ( − 2 ) ( m o d 6 ) 4 2 ≡ ( 4 ) ≡ ( − 2 ) ( m o d 6 ) 4 4 ≡ ( 4 2 ) ≡ ( 4 ) ≡ ( − 2 ) ( m o d 6 ) ⇒ 4 1 6 ≡ ( − 2 ) ( m o d 6 ) ⇒ 4 3 2 ≡ ( − 2 ) ( m o d 6 ) ⇒ 4 9 6 ≡ ( − 8 ) ≡ ( 4 ) ( m o d 6 ) .
4/6 remainder =2==> (4^2)/6 remainder=4==> (4^3)/6 remainder=4==> (4^4)/6 remainder=4==> ... now we got the pattern. 2,4,4,4,...,4. only 4/6 that remainder 2.
so,(4^96)/6 remainder = 4
96 divide 6 is 16 so it is finite has no remainder. the only no. left is 4 so my answer is 4. thats how i got it but i know it has no mathemaical basis
4^96=1^96=1 modulo 3. 4^96=0 modulo 2.
Therefore 4^96 is one more than a multiple of three and even.
Considering integers modulo 6, of the integers 0,1,2,3,4,5 only 4 satisfies the conditions therefore 4^96=4 modulo 6
Just we can find 4^6 =4096. Then 4096/6 remainder=4
4^(96)=4^(16) * 4^(6). Now the remainder when divided by 6 is equal to the remainder in case of 4^(16). Remainder in case of 4^(16) is equal to remainder in case of 4^(4) which is again equal to the remainder in case of 4^(2). So, 16 i.e. 4^2=(6*2)+4. So 4 is the answer.
By using the Totient function and CRT we can compute mod 6 as mod 3 and mod 2. Any power of 4 is congruent to 0 mod 2 so 4^96 is 0 mod 2. For 4^96 mod 3 apply the Totient function. Since 3 is prime Φ(3) is just 3-1 or 2. so 4^2 is congruent to 1 mod 3. There fore (4^2)^48=1^48 mod 3 or 1 mod 3. So what is the smallest integer that is divisible by 2 and one more than a multiple of 3? 4.
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We can see that 4 2 ≡ 4 ( m o d 6 ) So 4 9 6 ≡ 4 4 8 ≡ 4 2 4 ≡ 4 1 2 ≡ 4 6 ≡ 4 3 ( m o d 6 ) The question is equivalent to 6 4 ( m o d 6 ) which is just 4