Question
Question: The number 1992<sup>1998</sup> – 1955<sup>1998</sup> – 1938<sup>1998</sup> + 1901<sup>1998</sup> is ...
The number 19921998 – 19551998 – 19381998 + 19011998 is divisible by k. Then value of k is-
A
666
B
3996
C
5994
D
None of these
Answer
666
Explanation
Solution
1992n – 1938n is divisible by (1992 – 1938) i.e., 54
1955n – 1901n is divisible by (1955 – 1901) i.e., 54
Ž The given number is divisible by 54.
1992n – 1955n is divisible by (1992 – 1955) i.e., 37
1938n – 1901n is divisible by (1938 – 1901) i.e., 37
The given number is divisible by 37
Ž Hence the given number is divisible by
54 × 37 = 1998
Ž divisible by 666 [since 666 × 3 = 1998].