A rectangular park 60 m long and 40 m wide has two concrete crossroads running in the middle of the park and rest of the park has been used as a lawn. If the area of the lawn is 2109 sq. m, then what is the width of the road?

1.5m

2.5m

3.5m

4.5m

Explanation:

Let the width of the road be x meters.

Then, (60 – 2x)(40 – 2x) = 2109

=> 2400 – 200x + 4$x^{2}$ = 2109

=> 4$x^{2}$ – 200x + 291 = 0

=> x = (200 ± 188) / 8 = 1.5 or 48.5

But width of road cannot be greater than breadth of the park. Thus, width of road = 1.5m.