A rectangular pool  meters wide and  meters long is surrounded by a walkway of uniform width. If the total area of the walkway is  square meters, how wide, in meters, is the walkway?

A.43m

B. 4.3m

C.3m

D.3.5m

C. 3m

area of the rectangular pool = length * breadth = 60*20 = 1200 m^2

given the area of walkway is 516 m^2,

so total area = 1200 + 516 = 1716 m^2

let the width of walkway be x, as the walkway is uniform in width, the length of total area will be = 60 + 2x and breadth of total area will be = 20 + 2x

now, 1716 = (60 + 2x)*(20+2x)

1716 = 1200 + 120x + 40x + 4x^2

We get, x = 3 or -43

since width cannot be negative,

the width of the walkway is 3m.