Question

9) A cylindrical pipe has an outer diameter of
14 cm and inner diameter of 11.2 cm. Its
length is 20 cm. It has to be painted on its
outer and inner surfaces, as well as on its
rims at the top and bottom. If the rate of
painting is 70.07 per cm’, find the total cost
of painting the pipe.

Answer 1

Answer:

Question:-

A cylindrical pipe has an outer diameter of 14 cm and inner diameter of 11.2 cm. Its length is 20 cm. It has to be painted on its outer and inner surfaces, as well as on its rims at the top and bottom. If the rate of painting is 70.07 per cm’, find the total cost of painting the pipe.

Answer:-

Solution:-

Total area to be painted = outer surface+ inner surface + rims of top and bottom;

Lateral surface are of cylinder =2 pi × h × r

Outer surface = 2×3.14×20×14 = 1758.4 sq. cm.

Inner surface = 2×3.14×20×11.2 = 1406.72 sq.cm.

Surface of top rim = pi (14^2-11.2^2) =221.58 sq cm.

Surface of top rim = same as top rim =

221.58 sq. cm

Total area = 1758.4+1406.72+2×221.58 = 3608.28 sq. cm

per sq. painting cost = 0.07 rupees;

Total cost to painting= 3603.28×0.07 = 252.57 rupees.

Step-by-step explanation:

$Hope \: it \: helps.$

Answer 2

Answer:

1,26,529.6032 /-

Step-by-step explanation:

Total cost of painting the pipe = Cost * (Outer Surface + Inner Surface Area + Area of 2 rings)

Outer surface area = 2πRh

= 2*22/7*7*20

= 880 cm²

Inner Surface Area = 2πrh

= 2*22/7*5.6*20

= 704 cm²

Area of two rings = 2 * 2π(R²-r²)

= 4*22/7(7²-(5.6)²)

= 221.76 cm²

Total Cost of painting = 70.07 * (880+704+221.76)

= 1,26,529.6032 /-