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?
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:
76 comments Page 7 of 8.
Sana said:
2 decades ago
hey golu..
we have two options for the value of 'x' :
x=97 or x=3;
97 is not chosen as value of 'x' because the width of the rectangular park is only 40 m.
and only the value 'x=3' is less than 40 m.
so, 'x=97' is not possible at all.
we have two options for the value of 'x' :
x=97 or x=3;
97 is not chosen as value of 'x' because the width of the rectangular park is only 40 m.
and only the value 'x=3' is less than 40 m.
so, 'x=97' is not possible at all.
Amrut said:
2 decades ago
thnks ayoosh & nakul
Golu said:
2 decades ago
Why 97 was not taken as answer?
Manish said:
2 decades ago
Thanks ayoosh.
Nayan said:
2 decades ago
Thnks nakul.
Nakul gowda said:
2 decades ago
60x + 40x includes the intersection part twice..so to include the intersection part only once, subtract area of intersection part once, ie, x^2....got it yet..
Sujay ramesh said:
2 decades ago
Thanks ayoosh. Your explanation is good :).
Ayoosh said:
2 decades ago
If we dont subtract the X^2 THEN the area of intercrossing will be doubled since its accountd in area of both roads !! thats why we subtract x^2
(2)
Jhola said:
2 decades ago
Very good ayoosh.
Ayoosh said:
2 decades ago
For all having probs in the 60x + 40x - x^2!!!!
See road is a rect. and they are intercrossing. let the width be x, then for one road area will be 40x and for the other road will be 60x since 60 and 40 will be the lengths of road.
now, we area of roads is 291 m2, so
ar(road1) + ar(road2) - ar(intercrossing)
60x + 40x - x^2 = 291 and then on you can find the ans
See road is a rect. and they are intercrossing. let the width be x, then for one road area will be 40x and for the other road will be 60x since 60 and 40 will be the lengths of road.
now, we area of roads is 291 m2, so
ar(road1) + ar(road2) - ar(intercrossing)
60x + 40x - x^2 = 291 and then on you can find the ans
(9)
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