For which of the following, any number of the form 10𝑛−110𝑛−1 is divisible by 11.For even value of NN=multiple of 11All value of NFor odd value of N
Question
For which of the following, any number of the form is divisible by 11?
- For even value of N
- N = multiple of 11
- All value of N
- For odd value of N
Solution
The number of the form 10^n - 1 is divisible by 11 for all values of N.
Here's why:
Consider the formula for the sum of a geometric series: a + ar + ar^2 + ... + ar^(n-1) = a(1 - r^n) / (1 - r), where a is the first term, r is the common ratio, and n is the number of terms.
In our case, a = 1, r = 10, and n = N. So, our series becomes 1 + 10 + 10^2 + ... + 10^(N-1) = 10^N - 1 / (10 - 1) = 10^N - 1 / 9.
Now, let's consider the divisibility rule for 11: a number is divisible by 11 if and only if the difference between the sum of its digits at odd positions and the sum of its digits at even positions is a multiple of 11.
In our series, the sum of the digits at odd positions is (1 + 0 + 1 + ... + 0 + 1) = N/2 (rounded up to the nearest integer), and the sum of the digits at even positions is (0 + 1 + 0 + ... + 1 + 0) = N/2 (rounded down to the nearest integer). So, their difference is either 0 or 1, depending on whether N is even or odd.
Therefore, 10^N - 1 is divisible by 11 for all values of N.
Similar Questions
For which of the following, any number of the form 10𝑛−110𝑛−1 is divisible by 11.For even value of NN=multiple of 11All value of NFor odd value of N
A number is divisible by 11 if the _______________ of the sums of alternating digits is 0 or 11.
Find which of the following number is divisible by 11?*246542415624146532426513
Which one of the following numbers is exactly divisible by 11?*4 points235641245642315624415624
Which of the following number is divisible by 12?45795840457948504579588045794860None of these
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.