Aptitude - Area - Discussion

Discussion Forum : Area - General Questions (Q.No. 15)
15.
A tank is 25 m long, 12 m wide and 6 m deep. The cost of plastering its walls and bottom at 75 paise per sq. m, is:
Rs. 456
Rs. 458
Rs. 558
Rs. 568
Answer: Option
Explanation:

Area to be plastered = [2(l + b) x h] + (l x b)
= {[2(25 + 12) x 6] + (25 x 12)} m2
= (444 + 300) m2
= 744 m2.

Cost of plastering = Rs. 744 x 75 = Rs. 558.
100

Discussion:
24 comments Page 3 of 3.

Prayag said:   6 years ago
Hi Ben,

In the question, it is 75 Paise per sq. m and the option are in Rupees. So if you divide by 100 to convert 75 Paise to Rs i.e 0.75 Rs.

Therefore the answer is 744 sq.m. x Rs. 0.75 = Rs.558.

Thanks
(2)

Koks said:   6 years ago
How come 75/100?
(1)

Avijit.AD said:   6 years ago
Thanks, @Salman.

That explanation is really easy to understand.

Tasrash said:   4 years ago
Forget the perimeter. the tank depth is 6m and it surrounded by 4 walls.
the two walls is 6x12 and another two walls is 6 x 25 in size.
So total wall area is= (2x6x12)+(2x6x25) = 444 sq m.
Now 4 walls completed plastering.
you have only the bottom side.

Area of bottom= 12x25 = 300 sq.m.
So Total area = 300 + 444 = 744 sq.m.
Now total cost is = 744 x 0.75 RS..

Draw a 3d sketch of a hollow rectangular pipe you will understand!
(19)


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