Solution
We need to find the value of N. Since we are not given much information, let us analyse both the statements one by one.
Statement-1 “
N is the least integer such that (0.0036) * (0.00078) * (6370) * 10^N is an integer.”
Let us write \((0.0036) * (0.00078) * (6370) * 10^N\) in simplified form.
•\(= (0.0036) * (0.00078) * (6370) * 10^N\)
• = \((0.0036) * (0.00078) * (637) * 10^N*10\)
• = \((0.0036) * (0.00078) * (637) * 10 ^{(N+1)}\)
• = \((36* 10^{-4}) * (78*10^{-5}) *637* 10^{(N+1)}\)
• = \((36) * (78 ) *637* 10^{(N+1-4-5)}\)
• = \(36*78* 637*10^{(N-8)}\)
The power of 10 cannot be negative. Hence, for the least value of N, N-8 should be equal to 0.
Therefore,
Statement 1 alone is sufficient to answer the question.
Statement-2 “
N is a factor of 64 and N has exactly 4 factors.”
A number having \(4\) factors can be written in the two forms.
• \(N= p1* p2\), where \(p1, p2\)are prime numbers
• \(N= p^{3}\), where \(p\) is a prime number.
Since\(N\) is a factor of \(64\), therefore \(N\) has only \(1\)prime factor, that is \(2\).
Hence, \(N= 2^3=8\)
Therefore,
Statement 2 alone is sufficient to answer the question.Thus, we can find the answer by each of the statement alone.
Answer: D