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Aptitude · Q112

Number System

Competitive Exams · Aptitude · question 112

Q112

If (-1)n + (-1)4n = 0, then n is

A.
Any positive integer
B.
Any negative integer
C.
Any odd natural number
Answer
D.
Any even natural number

Answer: Option C

Solution

Answer: Option C
Solution:
Putting n = 1, 2, 3, 4, 5 . . . .
n = 1 in the given equation
(-1)1 + (-1)4 × 1 = 0
Or, -1 + 1 = 0

n = 2
(-1)2 + (-1)4 × 2 = 0
Or, 1 + 1 ≠ 0

n = 3,
-1 + 1 = 0
We will see that the given condition will be satisfy only for ANY ODD NATURAL NUMBER.