is problem 2 d??
if you loook at 0,1 on the real number line, there both reflected at a 1/2 with 0,1 being the extreme points. hence 1/2 is the mid point of (0,1)
for a ) add 1/4 to 0 and you get a 1/4. Subtract 1/4 from 1 and you get 3/4.
the pair (1/4, 3/4) the mid point is 1/2.
for b) add...