Math Problem Statement

When a number is successively divided by 5, 6, and 3, the respective remainders are 2, 3, and 1. What will be the remainder if the order of divisors is reversed?

Solution

To solve this problem, let's determine the remainders when the order of divisors (5, 6, and 3) is reversed to (3, 6, 5). Here's how we can work through the solution step by step.

Step-by-Step Solution:

1. Original Divisor Order (5, 6, 3):

We are given:

  • The number NN gives a remainder of 2 when divided by 5.
  • The quotient from the first division is then divided by 6, giving a remainder of 3.
  • The resulting quotient is divided by 3, giving a remainder of 1.

Let:

  • N=5a+2N = 5a + 2 (from the first division, remainder 2),
  • The quotient aa satisfies a=6b+3a = 6b + 3 (from the second division, remainder 3),
  • Finally, bb satisfies b=3c+1b = 3c + 1 (from the third division, remainder 1).

Substituting these equations:

  • b=3c+1b = 3c + 1,
  • a=6(3c+1)+3=18c+6+3=18c+9a = 6(3c + 1) + 3 = 18c + 6 + 3 = 18c + 9,
  • N=5(18c+9)+2=90c+45+2=90c+47N = 5(18c + 9) + 2 = 90c + 45 + 2 = 90c + 47.

Thus: N=90c+47.N = 90c + 47.

2. Reversed Divisor Order (3, 6, 5):

Now, let's compute the remainders when N=90c+47N = 90c + 47 is divided by 3, 6, and 5 in reverse order.

  • First Division (by 3): 90c+47mod3=(90cmod3)+(47mod3).90c + 47 \mod 3 = (90c \mod 3) + (47 \mod 3). Since 90cmod3=090c \mod 3 = 0 (90 is divisible by 3), and 47mod3=247 \mod 3 = 2, the remainder is: Remainder=2.\text{Remainder} = 2.

  • Second Division (by 6): Divide 90c+473\frac{90c + 47}{3}, which is 30c+1530c + 15. The remainder when 30c+1530c + 15 is divided by 6: (30cmod6)+(15mod6)=0+3.(30c \mod 6) + (15 \mod 6) = 0 + 3. The remainder is: Remainder=3.\text{Remainder} = 3.

  • Third Division (by 5): Divide 30c+156\frac{30c + 15}{6}, which simplifies to 5c+2.55c + 2.5. We focus only on the integer part 5c+25c + 2. When 5c+25c + 2 is divided by 5: (5cmod5)+(2mod5)=0+2.(5c \mod 5) + (2 \mod 5) = 0 + 2. The remainder is: Remainder=2.\text{Remainder} = 2.

Final Answer:

The remainders when the order is reversed (3, 6, 5) are 2, 3, 2.

Correct Option:

a. 2, 3, 2


Would you like further clarification or a breakdown of any specific part? Here are some related questions to deepen understanding:

  1. How do modular arithmetic properties help in solving remainder problems?
  2. Can the solution be generalized for other divisor and remainder combinations?
  3. What is the mathematical significance of reversing the order of operations?
  4. How would the result change if the divisors were not relatively prime?
  5. What strategies can simplify handling such chained remainder problems?

Tip: Modular arithmetic is powerful in solving these problems. Always simplify step by step while keeping track of intermediate results to avoid errors.

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Math Problem Analysis

Mathematical Concepts

Modular Arithmetic
Number Theory

Formulas

Remainder when dividing a number N: N = divisor × quotient + remainder

Theorems

Properties of modular arithmetic
Successive division algorithm

Suitable Grade Level

Grades 9-12