Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 9)
9.
A cistern 6m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is:
Answer: Option
Explanation:
| Area of the wet surface | = [2(lb + bh + lh) - lb] |
| = 2(bh + lh) + lb | |
| = [2 (4 x 1.25 + 6 x 1.25) + 6 x 4] m2 | |
| = 49 m2. |
Discussion:
40 comments Page 2 of 4.
Rakhshanda Khan said:
1 decade ago
1.25 is height and 6 m is length of the tank. So we must take whole 6 m length while we are calculating it. Because whole lower most part of the tank is wet. That's why we are taking whole 6 m.
Punit said:
1 decade ago
Is it a cuboid ..? because 2(lb+bh+lh) is the formulae of a surface area of cuboid. I didnt get why are we subtracting lb from it ? Can anyone help me out with an pictorial diagram ?
Murali Krishna R said:
1 decade ago
We have 5 wet sides i.e., complete bottom portion (6mx4m = 24m2) and four walls (6mx1.25mx2 sides = 15m2 and 4mx1.25mx2 sides = 10m2).
Totally = 24+15+10 = 49m2.
Totally = 24+15+10 = 49m2.
Narinder said:
9 years ago
@Vyom:
Question is just about the wet area. If there is any question regarding total height then it Total length or something should be mentioned accordingly.
Question is just about the wet area. If there is any question regarding total height then it Total length or something should be mentioned accordingly.
Amrit said:
1 decade ago
Just imagine that the cuboid is full but the upper surface was empty
So we have to minus that part and take the l=6,b=4,h=1.25
I think now you got it.
So we have to minus that part and take the l=6,b=4,h=1.25
I think now you got it.
Ashwini said:
1 decade ago
@kittu : [2(lb + lh + bh)] - (upper most surface of water)[lb]
2lb + 2lh + 2bh - lb
2(bh + lh) + lb
hope ya gt it..!!
2lb + 2lh + 2bh - lb
2(bh + lh) + lb
hope ya gt it..!!
Kanna29 said:
3 years ago
@All.
Here, The uppermost surface also has some specific height. Then why everyone not considering it , just multiple l*b and not h?
Here, The uppermost surface also has some specific height. Then why everyone not considering it , just multiple l*b and not h?
(2)
Mohammad Asif said:
3 years ago
@All.
It should be clearly given that tha water filling height is measured from top or bottom of the container.
Am I right?
It should be clearly given that tha water filling height is measured from top or bottom of the container.
Am I right?
(8)
Rahul said:
1 decade ago
Confusion
the part that is not wet might also contain some height so why only LB
H should be included i think so?
Plz explain
the part that is not wet might also contain some height so why only LB
H should be included i think so?
Plz explain
Gowsank said:
1 decade ago
The question is about wet surface area, then why do they subtract the lb. ?or they are asking about the wall surface alone.
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