in Quantitative Aptitude edited by
1,349 views
0 votes
0 votes

Answer the question on the basis of the information given below:

A city has two perfectly circular and concentric ring roads, the outer ring road (OR) being twice as long as the inner ring road (IR). There are also four (straight line) chord roads from $\text{E1},$ the east end point of OR to $\text{N2}$, the north end point of IR; from $\text{N1}$, the north end point of OR to $\text{W2}$, the west end point of IR; from $\text{W1}$, the west end point of OR, to $\text{S2}$, the south end point of IR; and from $\text{S1}$, the south end point of OR to $\text{E2}$, the east end point of IR. Traffic moves at a constant speed $30 \pi \: \text{km/hr}$ on the OR road, $20 \pi \: \text{km/hr}$ on the IR road, and $15 \sqrt{5} \: \text{km/hr}$ on all chord roads.

The ratio of the sum of the length of all chord roads, to the length of the outer ring road is

  1. $\sqrt{5} : 2$
  2. $\sqrt{5} : -2$
  3. $\sqrt{5} : \pi$
  4. None of these
in Quantitative Aptitude edited by
13.4k points
1.3k views

1 Answer

0 votes
0 votes
Ans: C

length of OR = 2l (let) => length of IR = l

radius of OR = 2r (let) => radius of IR = r (radius is proportional to circumference)

=> length of chord = (r^2 + (2r)^2)^(1/2) = r(5^(1/2))

=> sum of length of all chords / length of OR = 4r(5^(1/2))/4(pi)r = sqrt(5) / (pi)
28 points

Related questions

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true