Find the number of digits in 8^57. (Given log10 2 = 0.3010)

Difficulty: Easy

Correct Answer: 52

Explanation:


Introduction / Context:
We again use the digit-count identity: digits = floor(log10 N) + 1. Express 8^57 as a power of 2 to leverage the provided log10 2 value.


Given Data / Assumptions:

  • N = 8^57 = (2^3)^57 = 2^171.
  • log10 2 = 0.3010.


Concept / Approach:

  • Compute log10(2^171) = 171 * 0.3010.
  • Apply digits = floor(log10 N) + 1.


Step-by-Step Solution:

log10 N = 171 * 0.3010 = 51.471Digits = floor(51.471) + 1 = 51 + 1 = 52


Verification / Alternative check:
Since 10^51 < N < 10^52 and it is not an exact power of 10, the digit count must be 52.


Why Other Options Are Wrong:

  • 50, 51, 53 result from rounding errors or dropping the +1.


Common Pitfalls:

  • Using 0.3 instead of 0.3010 gives 51.3 and still yields 52 digits, but coarser approximations can mislead if rounding is mishandled.


Final Answer:
52

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