Answer:
Let x be the breadth of the rectangular field.
The length of the field is 2x.
We know that the perimeter of the rectangular field is (2x + 2x) = 4x.
Meghna jogged 5 times around the field, so she covered a distance of 4x km.
We know that 4x = 3km.
So, x = 0.75km, and the length of the field is 2x = 2(0.75km) = 1.5km.