From the question it is given that,
Length of a rectangular field is 250m
Width of rectangular field = 150 m
Perimeter of rectangle = 2 × (length + breadth)
= 2 × (250 + 150)
= 2 × 400
= 800 m
Given that, Anuradha runs around this field 3 times = 3 × 800
= 2400 m
We know that, 1km = 1000 m
So, 2400/1000
= 2.4 km i.e. 2 km 400 m
Number of times Anurudha should run around the field to cover a distance of 4km = 4000/800
= 5 times
Therefore, 5 times Anurudha should run around the field to cover a distance of 4km.