CLEAR
Toprankers-Info

+91 7676564400

Mobile App

Get it on Google Play
Discussions
Select Date
Tags:

Articles

Discussions
Submit Discussion
prayag

· started a discussion

· 1 Months ago

DOUBT (Question: 111047.0 )

how you calculated the area of semi cylindrical top?

Question:
The cross-section of a railway tunnel is a rectangle 6m broad and 8m high, surounded by a semi-circle as shown in the adjoining figure. The tunnel is 35 m long. The cost of plastering the internal surface of the tunnel excluding the floor, at the rate of \(\unicode{x20B9} \)3 per m2 is :


Options:
A) \(\unicode{x20B9} \)2380
B) \(\unicode{x20B9} \)1780
C) \(\unicode{x20B9} \)2170
D) \(\unicode{x20B9} \)2670
Solution:
Ans: (d) (Area of parallel walls of height 8 m) + (Area of semi cylinderical top)

\(\therefore\) Area of wall \(=2\times(8\times35)=560m^2\)

\(\therefore\) Area of semi-cylinderical top = \(\frac{2\pi rh}{2}\)

\(=\cfrac{22}{7}\times3\times35=22\times3\times5=330\ m^2\)

\(\therefore\) Total area to be plastering \(=560+330=890m^2\)

\(\therefore\) Cost of plastering \(=\unicode{x20B9}(890\times3)=\unicode{x20B9}2670 \)

Knowledge Expert

· commented

· 1 Months ago

Dear student
Given answer is correct
In solution,
CSA of semi cylinder = 2 pi*r*h / 2 = pi*r*h
And follow the solution.

Best wishes
Team TR
-logo
We at aim to provide most comprehensive content & test for practice which is carefully divided into various chapters and topics to help you focus on your weak areas.Our Practice mock test gives you unmatched analytics to help you realize your strong areas,time management and improvement areas.Our Short & Crisp notes on each topic will help you to quickly revise the topic along with the tips & tricks of the exams.
More About
-Info
-Info

Mobile App

Get it on Google Play
About Us Campus Ambassador Careers Contact Us Refund Policy

All Rights Reserved Top Rankers

User Policy
Disclaimer
Terms & Conditions