Question

A container open at the top, is in the form of a frustum of a cone of height 24 cm with radii of its lower and upper circular ends as 8 cm and 20 cm respectively. Find the cost of milk which can completely fill the container at the rate of Rs 21 per litre. (Use $(\pi=\frac{22}{7})$)

Answer 1

Answer:

The cost of milk which can completely fill the container is ₹ 329.49

Step-by-step explanation:

SOLUTION :

Given:

Radius (R) of upper end of the frustum of cone  = 20 cm

Radius(r) of the lower end of the frustum of cone = 8 cm

Height of The frustum(h) = 24 cm

Volume of the container ( frustum) = 1/3πh[R² + r² + R×r]

= ⅓ × 22/7 × 24 [20² + 8² + 20×8]

= (22×8)/7 [400 + 64 + 160]

=  (22×8)/7 × 624

= 109824/7  

= 15689.14 cm³

= 15689.14/1000  

[1 cm³ = 1/1000 l]

= 15.69 l

Volume of the container ( frustum)=15.69 l

Cost of 1 L of  milk = ₹ 21

Cost of 15.69 l of  milk = 15.69 × 21  = ₹ 329.49

Hence, the cost of milk which can completely fill the container is ₹ 329.49.

HOPE THIS ANSWER WILL HELP YOU….

Answer 2

Answer:

Given: h=24 cm

Upper radius = r

1

=20

Lower radius = r

2

=8

Volume of frustum of a cone =

3

1

πh[r

1

2

+r

2

2

+r

1

r

2

]

=

3

1

×

7

22

×24[20

2

+8

2

+20×8]

= 15689.14 cm

3

= 15.69 litre

The cost of milk which can completely fill the container at the rate of Rs.21 per litre = 21×15.69=Rs.329.49