Question

a rectangular garden is 115 * 90 m.it has two roads, each 6 m wide, running in middle of it, one parallel to its length and other parallel to its breadth.find the cost of constructing the roads at $ 100 per m

Answer 1

Explanation:

so, the first road is 115 m long, the second is 90 m long.

we should be finished, if we multiply each road length by $100, right ?

well, not quite.

because the 2 roads overlap. for this overlap area we don't need to pay twice.

we have the choice : to which of the 2 roads do we assign the overlap area ?

let's "give" it to the longer road.

so, the cost for the longer road is simply

115 × 100 = $11,500

the cost for the shorter road is then without the overlap area (6 meters : the width of the other road)

(90 - 6)×100 = 84×100 = $8,400

in total the costs are

$11,500 + $8,400 = $19,900