What is the remainder when 1044 * 1047 * 1050 * 1053 is divided by 33?...
You can solve this problem if you know this rule about remainders.
Let a number x divide the product of A and B.
The remainder will be the product of the remainders when x divides A and when x divides B.
Using this rule,
The remainder when 33 divides 1044 is 21.
The remainder when 33 divides 1047 is 24.
The remainder when 33 divides 1050 is 27.
The remainder when 33 divides 1053 is 30.
∴ the remainder when 33 divides 1044 * 1047 * 1050 * 1053 is 21 * 24 * 27 * 30.
Note: The remainder when a number is divided by a divisor 'd' will take values from 0 to (d - 1). It will not be equal to or more than 'd'.
The value of 21 * 24 * 27 * 30 is more than 33.
When the value of the remainder is more than the divisor, the final remainder will be the remainder of dividing the product by the divisor.
i.e., the final remainder is the remainder when 33 divides 21 * 24 * 27 * 30.
When 33 divides 21 * 24 * 27 * 30, the remainder is 30.
Choice C is the correct answer.
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What is the remainder when 1044 * 1047 * 1050 * 1053 is divided by 33?...
Solution:
We know that any number which is divisible by 33 is also divisible by 3 and 11. So, we need to check the divisibility of the given expression with 3 and 11.
Divisibility by 3:
The sum of the digits of the number should be divisible by 3 for the entire number to be divisible by 3.
1044 → 1 + 0 + 4 + 4 = 9
1047 → 1 + 0 + 4 + 7 = 12
1050 → 1 + 0 + 5 + 0 = 6
1053 → 1 + 0 + 5 + 3 = 9
The sum of the digits of all the numbers is not divisible by 3. Hence, the given expression is not divisible by 3.
Divisibility by 11:
The difference between the sum of the alternate digits of the number should be either 0 or a multiple of 11 for the entire number to be divisible by 11.
1044 → (1 + 4) - (0 + 4) = 1
1047 → (1 + 7) - (0 + 4) = 4
1050 → (1 + 5) - (0 + 0) = 6
1053 → (1 + 3) - (0 + 5) = -1
The difference of the alternate digits of the numbers is not 0 or a multiple of 11. Hence, the given expression is not divisible by 11.
Therefore, the given expression is not divisible by both 3 and 11.
Using Chinese Remainder Theorem:
We can use the Chinese Remainder Theorem to find the remainder when the expression is divided by 3 and 11.
Remainder when divided by 3:
1044 * 1047 * 1050 * 1053 ≡ 0 * 0 * 0 * 0 ≡ 0 (mod 3)
Remainder when divided by 11:
1044 ≡ 6 (mod 11)
1047 ≡ 9 (mod 11)
1050 ≡ 0 (mod 11)
1053 ≡ 3 (mod 11)
1044 * 1047 * 1050 * 1053 ≡ 6 * 9 * 0 * 3 ≡ 0 (mod 11)
Now, we need to find a number which is congruent to 0 modulo 3 and 0 modulo 11.
Using the Chinese Remainder Theorem, we can find such a number.
Let N = 3 * 11 = 33
Let a1 = 11, a2 = 3
Let b1 = 0, b2 = 0
Since gcd(a1, a2) = 1, we can find two integers c1 and c2 such that c1 * a1 + c2 * a2 = 1.
We can use the Extended Euclidean Algorithm to find c1 and c2.
11 * 3 + (-1) * 33 = 0
c1 = 3, c2 = -1
Therefore, the solution to the congruences is given by:
x ≡ b1 * c2 * a2 + b2 * c1
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