Answer:
1.5 m
Step-by-step explanation:
Length. L = 12 m
Width, W = 16 m
Area, A = 12 x 16 = 192 m^2
Let the width of pavement be d.
The new length, L' = 12 + 2d
the new width, W' = 16 + 2d
New Area, A' = L' x W' = (12 + 2d)(16 + 2d) = 192 + 56 d + 4d^2
Difference in area = A' - A
285 = 192 + 56 d + 4d^2 - 192
93 = 56 d + 4d^2
4d^2 + 56 d - 93 = 0
![d = \frac{-56\pm \sqrt{56^(2)+4* 4* 93}}{8}](https://img.qammunity.org/2020/formulas/physics/high-school/o39yd6tuvpc5kry7yeluhzo0t0tvlrz2tj.png)
\
d = 1.5 m
Thus, the width of the pavement is 1.5 m.