Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :
- Statement I is false but Statement II is true
- Both Statement I and Statement II are false
- Both Statement I and Statement II are true
- Statement I is true but Statement II is false
Answer
(3) Both Statement I and Statement II are true
Solution
Statement I: for odd n, an + bn is divisible by a + b.
2513 + 313 is divisible by 25 + 3 = 28, and 2013 + 813 is divisible by 20 + 8 = 28
the sum is divisible by 28, hence by 7. Statement I is true.
Statement II: let (7 + 4 3)25 = I + f, 0 f < 1, and (7 - 4 3)25 = f'
0 < 7 - 4 3 < 1 0 < f' < 1
I + f + f' = 2 [25C0 725 + 25C2 723(4 3)2 + ] = even integer
f + f' is an integer with 0 < f + f' < 2 f + f' = 1
I = even - 1 = odd. Statement II is true.
Answer: (3)