If n is a whole number greater then 1, then n2 (n2 - 1) is always divisible by -
A. 16
B. 12
C. 10
D. 8
Answer: Option B
Solution(By Examveda Team)
n2(n2 - 1)put n = 2
= 22(22 - 1)
= 4(4 - 1)
= 4 × 3
= 12
Check the option it is divisible by 12.
$$\eqalign{ & {\text{Take n = 3}} \cr & \Rightarrow {{\text{3}}^3}\left( {{3^3} - 1} \right) \cr & \Rightarrow 9\left( {9 - 1} \right) \cr & \Rightarrow 9 \times 8 = 72 \cr & {\text{It is divisible by 12}} \cr & {\text{So 12 is answer}} \cr} $$
Related Questions on Number System
Three numbers are in ratio 1 : 2 : 3 and HCF is 12. The numbers are:
A. 12, 24, 36
B. 11, 22, 33
C. 12, 24, 32
D. 5, 10, 15
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