Question 711621
length of the walkway = 2m.
length of the plot    = 20m
width of the plot     = 12m

Solution : Total width with walkway = 12 + 2 + 2 = 16m
           Total length with walkway = 20 + 2 + 2  = 24m

Total area of plot and walkway = 16 * 24 sq.m ------eq.1
Total area of plot             = 12 * 20 sq.m ------eq.2

Total area covered by walkway =  eq.1 - eq.2 = 16*24 - 12*20 = 144 sq.m