If a and b are two odd positive integers, by which of the following integers is (a4 - b4) always divisible?
3
6
8
12
is
10
100
1000
None of these
B.
100
Let a = 0.05, b = 0.41 and c = 0.073
If a and b are odd numbers, then which of the following is even?
a + b + ab
a + b - 1
a + b + 1
a + b + 2ab