Answer: 4 m/s (towards East)
Explanation:
The velocity of man jogging with respect to a stationary observer, Vm = +2.5 m/s (Eastwards)
The velocity of woman jogging with respect to a stationary observer, Vw = -1.5 m/s (Westwards)
In woman's frame of reference, the man would be jogging relatively faster in the opposite direction as she is in motion herself.
From the woman's frame of reference, the man's velocity:
Vmw = Vm-Vw = +2.5 m/s - (-1.5 m/s) = +4.0 m/s (Eastwards)