Question 805748
the area of plot = 48 m^2

ratio is 1/3 

Width = 1/4 * 48 = 12m
length = 3times 12 = 36m

the width is x

Inner garden length = 36-2x
inner garden width = 12-2x

Area of garden = (36-2x)(12-2x)
Land scaping the garden $3 / m^2

Cost of landscaping = 3(36-2x)(12-2x)

Cost of pavement

area of pavement =  total area - area of inner garden

48- 3(36-2x)(12-2x)

cost of pavement = $2 /m^2

Cost of pavement = 2(48-3(36-2x)(12-2x))

Total cost

total cost C= cost of pavement + cost of landscaping inner garden

C= 2(48-3(36-2x)(12-2x)) + 3(36-2x)(12-2x)
= 96-6(36-2x)(12-2x)) + 3(36-2x)(12-2x)

simplify if necessary