What is the remainder when the number formed by writing …

Mathematics Questions

What is the remainder when the number formed by writing the digits ‘147’ 841 times is divided by 11?

Short Answer

The long number ‘147’ is repeated 841 times, leading to a total digit sum of 10092. When divided by 11, the remainder is 5.

Step-by-Step Solution

Step 1: Understanding the Number

To begin solving the problem, recognize that the long number consists of the digits ‘147’ repeated 841 times. This means we should treat it as one continuous sequence: 147147147… for a total of 841 repetitions. Understanding this structure helps us simplify the calculations we need to perform.

Step 2: Finding the Sum of Digits

Next, apply the divisibility rule for 11 by first calculating the sum of the digits in ‘147’. The digits are:

  • 1
  • 4
  • 7

Sum these digits: 1 + 4 + 7 = 12. Since the digits of ‘147’ repeat 841 times, the total sum of all the digits will be: 12 ‚àöo 841 = 10092.

Step 3: Calculating the Remainder with 11

Finally, to find the remainder when 10092 is divided by 11, perform the division: 10092 ‚àö‚àë 11 = 917 with some remainder. Calculate the whole part: 917 ‚àöo 11 = 10087. The remainder is then found by subtracting: 10092 – 10087 = 5. Thus, the remainder when the number is divided by 11 is 5.

Related Concepts

Number Representation

A way of expressing a long number as a sequence of repeated digits, in this case, ‘147’ repeated 841 times.

Divisibility Rule

A mathematical principle used to determine whether one number can be evenly divided by another number without leaving a remainder; for 11, it involves understanding the sum of the digits.

Remainder

The amount left over after division when one number does not divide another exactly, which helps in checking divisibility.

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