Aptitude Contest - 13 With Answers

[HELP]

1. The length of canvas 1.1 m wide required to build a conical tent of height 14 m the floor area 346.5 sq. m is :

(a) 490 m
(b) 525 m
(c) 665 m
(d) 860 m

2. If the radius of the base and the height of a right circular cone are doubled, then volume becomes:

(a) 2 times
(b) 3 times
(c) 4 times -
(d) 8 times

3. If both the radius and height of a right circular cone are increased by 20%, its vol will be increased by :

(a) 20%
(b) 40%
(c) 60%
(d) 72.8%

4 . If the height of a right circular cone is increased by 200% and the radius of the I is reduced by 50%, then the volume of the cone:

(a) remains unaltered
(b) decreases by 25%
(c) increases by 25%
(d) increases by 50%


5.If the height of a cone be doubled and radius of base remains the same, then the ra of the volume of the given cone to that of the second cone will be:

(a) 1 : 2
(b) 2 : 1
(c) 1 : 8
(d) 8 : 1


Answers

2. B
   
3. D
   
4. D
   
5. B
   
6. A

Edited by: HELP

[wishes4u]

1 (b)
2 (d)
3 (d)
4 (b)
5 (a)

How wud I know whether my answers are correct or not

[keerthi]

2. If the radius of the base and the height of a right circular cone are doubled, then volume becomes:

(a) 2 times
(b) 3 times
(c) 4 times -
(d) 8 times

Volume increases by 8 times

[keerthi]

1. The length of canvas 1.1 m wide required to build a conical tent of height 14 m the floor area 346.5 sq. m is :

(a) 490 m
(b) 525 m
(c) 665 m
(d) 860 m

Sol: area of base = 346.5= pi*r^2
radius r= 10.5 m
height h = 14 m
slant height l = root of(14^2 + 10.5^2) = 17.5 m
Lateral surface area = pi*r*l = 577.26 sq m
now length of canvas required = 577.26/1.1 =525m

[keerthi]

3. If both the radius and height of a right circular cone are increased by 20%, its vol will be increased by :

(a) 20%
(b) 40%
(c) 60%
(d) 72.8%

let radius be r and height be h
volume = 1/3(pi*r^2*h)
if they are incresed by 20% then r = 1.2r and h =1.2h
now volume =1/3(pi*(1.2 r)^2*1.2h) = 1.728 (1/3*pi*r^2*h)
so increase in volume = 0.728 which is 72.8%

[keerthi]

4 . If the height of a right circular cone is increased by 200% and the radius of the I is reduced by 50%, then the volume of the cone:

(a) remains unaltered
(b) decreases by 25%
(c) increases by 25%
(d) increases by 50%

Ans) original height =h
increased height = 3h
original radius = r
reduced radius = 0.5r
now volume = 1/3(pi* (0.5r)^2*3h) = 0.75 (1/3*pi*r^2*h)
that is volume is0.75 of original volume
that is it decreased by 25 %

[keerthi]

5.If the height of a cone be doubled and radius of base remains the same, then the ra of the volume of the given cone to that of the second cone will be:

(a) 1 : 2
(b) 2 : 1
(c) 1 : 8
(d) 8 : 1

Volume of given cone = 1/3(pi*r^2*h)
volume of second cone =1/3(pi*r^2 *2h)
hence ratio = 1:2