I + f + f' is an even integer, where I is an integer, f and f' are proper positive
fractions (0 < f, f' < 1). Then the integer I is an odd number.
True
I + f + f' is an even integer
I is also an integer. For I + f + f' to be an integer, f + f' should also be an integer. The
only integer value it can take is 1, because 0 < f + f' < 2.
⇒ f + f' = 1
⇒ I is an odd integer