Solution:
Question 8: If m and n are the positive integers such that m is prime and n is composite. Then
A. m-n cannot be an even number
B. m-n cannot be odd number
C. mn cannot be even
D. (m+n)/m cannot be even
E. None of the above statements is true
According to this question, m and n are positive integers. Therefore, m and n cannot be equal to 0. Moreover, m is prime and n is composite or n also has factors other than 1 and number 'n' itself. We need to select the option in which the statement is true.
Considering the options:
Option A: m-n cannot be an even number. Let m = 13 and n = 9. Then, \(m - n = 13 - 9 = 4\), which is an even number. Thus, option A is eliminated.
Option B: m-n cannot be odd number. Let, m = 7 and n = 6. Then, \(m - n = 7 - 6 = 1\), which is an odd number. Thus, option B is eliminated.
Option C: mn cannot be even . This statement is also false. If m = 7 and n = 6 then, \(mn = 7*6 = 42\), which is even number. Thus, option C is eliminated.
Option D: \(\frac{(m+n)}{m}\) cannot be even. This statement is not true. If \(m = 2\) as 2 is the lowest prime number and \(n = 14\). Then, \(\frac{(m + n)}{m} = \frac{(2 + 14)}{2} = \frac{16}{2} = 8\), which is even number. Thus, option D is also eliminated.
Therefore, the correct answer is Option E that states 'None of the above statements is true'.