Question

A local park is 32 m long and its width is half of the length. It has two right-triangular grass lawns with the following dimensions. The local gardener wanted to renovate the park so he hired some men. The men agreed to work on the grass lawn at ₹​ 1.2 per sq metre and put new footpath at ₹ 0.80 per sq metre. What is the total cost the gardener will have to pay after the work is done?

• A. ₹​ 421.8
• B. ₹​ 431.2
• C. ₹​ 512
• D. ₹​ 368.4

Answer 1

The correct option is B ₹​ 431.2

The two triangles have different dimensions, hence different areas
Area of 1 triangle = $\frac{1}{2}\times 5\times 12=30m^2$
Area of the other triangle = $\frac{1}{2}\times 8\times 6=24m^2$
Total area of the triangular lawns = 30 + 24 = $54m^2$

Cost of working on the lawns = $1.2\times 54=₹64.8$

Length of the park, $l=32m$
Breadth of the park, $b=16m$
Total area of the park = $l\times b=32\times 16=512m^2$

Area of the footpath = Area of park - Area of the triangular lawns
$\Rightarrow 512-54\Rightarrow 458m^2$

Cost of putting new footpath = $458\times 0.8=₹366.4$

Total cost = 64.8 + 366.4 = ₹ 431.2