Aptitude - Area - Discussion

Discussion Forum : Area - General Questions (Q.No. 5)
5.
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?
2.91 m
3 m
5.82 m
None of these
Answer: Option
Explanation:

Area of the park = (60 x 40) m2 = 2400 m2.

Area of the lawn = 2109 m2.

Area of the crossroads = (2400 - 2109) m2 = 291 m2.

Let the width of the road be x metres. Then,

60x + 40x - x2 = 291

x2 - 100x + 291 = 0

(x - 97)(x - 3) = 0

x = 3.

Video Explanation: https://youtu.be/R3CtrAKGxkc

Discussion:
75 comments Page 8 of 8.

Tanya said:   1 decade ago
Its because the area of 2 roads has come out to be 291m2. Rest of the explaination has been given by prajwal.

Shreya said:   1 decade ago
My doubt is

60x+40x-x2=291?.

Prajwal said:   1 decade ago
I got it. Its because. 60 and 40 get multiplies to width and. Since there are two cross roads. There will be a common space for two roads. (width of two cross roads is width^2).

Lekshmi said:   1 decade ago
Same doubt as sai said above,

60x + 40x - x2 = 291?

60x+40x?

Sai said:   1 decade ago
What is the need of 60x + 40X -pow (x, 2) ?


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