Aptitude - Volume and Surface Area - Discussion

Thanks for all the given explanation of the answer.

Thank you all for the given explanation.

We have given l=15, b=12.
Area of ceiling + floor = Area of four wall,
2(l*b) = 2(12*h)+2(15*h),
( because opposites walls are of same area)
2(15*12)=2h(12+15),
h=180/27.

I cannot understand this, please explain.

Will anyone help me to getting this?

Anyone help me to understand this easily?

To simplify it, we can separate the equation and calculate the surface area and ceiling area which is 2(15*12)=360 in total. Now as per question, it says that 4 walls have a total area of 360.

Now, we have to find the height of wall. So lets assume height is x.

So as per question, (15*x)+(12*x)+(15*x)+(12*x)=360. (Which is equal to floor + ceiling area)
if we will solve this equation, we will get the height of wall as 20/3.

Now we can find the are of hall by 20*15*20/3 which is equal to 1200.

I didn't understand this! please explain it clearly.

Easy to understand now with the help of given explanation, Thank you all.

Thanks @Lokesh.