Answer :
The cumulative distance the bird travels is 4.4 km.
Time of motion of the bird
The time of motion of the bird is calculated from the principle of relative velocity.
distance covered by bird - distance of runner = distance between them
vb_t - vr_t = d
(vb - vr)t = d
where;
- t is the time of motion
(28.4 - 7.1)t = 3.3
21.3t = 3.3
t = 3.3/21.3
t = 0.155 hr
Distance traveled by the bird within this time
d = 0.155 hr x 28.4 km/h
d = 4.4 km
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