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Question
If 21998 – 21997 – 21996 + 21995 = k.21995, then the value of k is ______.
Options
1
2
3
4
Solution
If 21998 – 21997 – 21996 + 21995 = k.21995, then the value of k is 3.
Explanation:
Given, 21998 – 21997 – 21996 + 21995 = k.21995
⇒ `2^(1995 + 3) - 2^(1995 + 2) - 2^(1995 + 1) + 2^(1995) xx 1` = k.21995
⇒ 21995[23 – 22 – 21 + 1] = k.21995 ......[∵ am+n = am × an]
⇒ 21995[8 – 4 – 2 + 1] = k.21995
⇒ 3 = `(k.2^1995)/2^1995`
⇒ 3 = k or k = 3
So, the value of k is 3.
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