Answer:
1.5m
Step-by-step explanation:
Let the length of the pathway across all its side be x. This means we are adding a length of 2x to both the length and breadth to 12+2x and 16+2x respectively.
The new area thus becomes:
(12+2x)(16+2x) = 285
24x + 32x + 192 + 4x^2 = 285
4x^2 + 56x + 192 = 285
4x^2 + 56x + 192 - 285 =0
4x^2 + 56x -93 = 0
4x^2 + 62x - 6x - 93 = 0
2x( 2x + 31) - 3(2x + 31) = 0
(2x - 3)(2x + 31) = 0
This means x = 3/2 or -31/2
Since length cannot be negative , we choose the first and neglect the second meaning our answer is 3/2 which is 1.5 meters