If k2 - 1 is divisible by 8, then k is:
Question and options
If k2 - 1 is divisible by 8, then k is:
- a multiple of 4
- a natural number
- an even integer
- an odd integer
Answer and explanation
Correct answer: D - an odd integer
k^2-1 = (k-1)(k+1). If k is odd, these are consecutive even numbers, one a multiple of 4, so the product is divisible by 8. If k is even (including multiples of 4), k^2-1 is odd. So k is an odd integer; natural number is not forced (k = -1 works).
Practice for these exams
-
JIPMAT
Related question papers
Related exam syllabi
More solved explanations in Number series & simplification
- If \(n\) is an integer such that \(\frac{|n+6|-|n-3|}{\sqrt{100-n^3}} \geq 0\), then the number of possible values of \(n\) is __________
- If a, b, c are non-zero rational numbers such that abc = 1 and the denominators are non-zero, then the value of – (1 / (1 + a + b^(-1)) + 1 / (1 + c + a^(-1)) + 1…
- Find the missing term: 15, 16, 20, 29, 45, ?
- Which number in the following list is not a perfect cube of an integer? 8, 27, 64, 100, 125, 216, 343
- Find out the wrong number in 24, 27, 31, 33, 36