# The Cost of Painting the Total Outside Surface of a Closed Cylindrical Oil Tank at 50 Paise per Square Decimetre is Rs 198. the Height of the Tank is 6 Times the Radius of the Base of the Tank - Mathematics

Sum

The cost of painting the total outside surface of a closed cylindrical oil tank at 50 paise per square decimetre is Rs 198. The height of the tank is 6 times the radius of the base of the tank. Find the volume corrected to 2 decimal places.

#### Solution

Data given is as follows:

h = 6r

Total cost of painting=Rs.198

Painting rate= Rs.0.50 per square decimeter

We have to find the volume of the cylinder.

We know that,

Total Surface Area of the cylinder =  2pirh + 2pir^2

Also, it is given that,

Total cost of painting = 198

That is,

(Total Surface Area of the cylinder ) × Painting rate = 198

( 2pirh + 2pir^2 ) xx  Painting rate = 198

(2 pi rh + 2 pir^2) xx 0.50 = 198

(2pirh +2pir^2) = 396

In the above equation, let us replace h with 6r.

 12 pir^2 + 2pir^2=396

14 pir^2=396

14 xx 22/7 xx r^2=396

r =3 decimeters

h = 6r = 6 × 3 =18 decimeters

Volume of the cylinder = pir^2h

=22/7 xx 3 xx 3xx 18

Volume of the cylinder = 509.14dm3

Concept: Surface Area of Cylinder
Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Mathematics for Class 9
Chapter 19 Surface Areas and Volume of a Circular Cylinder
Exercise 19.2 | Q 8 | Page 21

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