Question 2.

Let n and m be two positive integers such that there are exactly 41 integers greater than 8m8^m and less then 8n8^n, which can be expressed as powers of 2. Then, the smallest possible value of n + m is

A
14
B
42
C
16
D
44

Question Explanation

Text Explanation

It is given that there are exactly 41 numbers, which can be expressed as the power of two, and exist between 8m8^m and 8n8^n, (where m, and n are positive integers, and m < n)

Hence, 23m2^{3m} < 41 numbers < 23n2^{3n}

Since, m is a positive integer, the least value of m is 1. Therefore, 23m2^{3m} = 232^3, hence, the 41 numbers between them are 242^4252^5262^6, ..., 2442^{44}

Then the lowest possible value of 8n8^n is 2452^{45}. Hence, the smallest value of n is 2452^{45} = 8n8^n => 23n2^{3n} = 2452^{45} => n = 15

Hence, the smallest value of m+n is (15+1) = 16

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