CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Question 4
A container, opened from the top and made up of a metal sheet, is in the form of a frustum of a cone of height 16 cm with radii of its lower and upper ends as 8 cm and 20 cm, respectively. Find the cost of the milk which can completely fill the container, at the rate of 20 per litre. Also find the cost of metal sheet used to make the container, if it costs 8 per 100 square centimetres.

Open in App
Solution


Height of frustum = 16 cm, R = 20 cm, r = 8 cm
Volume of frustum
=13πh(R2+r2+Rr)
=13π×16(202+82+160)
=13×227×16(400+64+160)
=13×227×16×624
=10459.42 cm3

Cost of milk at 20 per 1000 cubic cm
10.45942×20= 209.18

For calculating surface area, we need to find slant height which can be calculated as follows:
l=h2+(Rr)2
=162+(208)2
=256+144
=400=20 cm

Surface area of frustum
=π(R+r)l+πr2
=π[(R+r)l+r2]
=π[(20+8)20+82]
=π(560+64)
=227×624=1961.14cm2

Cost of metal sheet at ₹ 8 per 100 sq cm
= 19.6114×8= 156.89

flag
Suggest Corrections
thumbs-up
0
similar_icon
Similar questions
View More
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon