IMO Mathematics Olympiad Class 8: Questions 455  460 of 1029
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Question number: 455
Question
The dimensions of an open box are 30 cm, 20 cm and 11 cm. Its thickness is 2 cm. If 1 cubic cm of metal used in the box weights 1 gms, find the weight of the box.
Choices
Choice (4)  Response  

a.  1.99 kg 

b.  4.561 kg 

c.  1.860 kg 

d.  2.856 kg 

Question number: 456
Question
If the area of a triangle with base a is equal to area of a square of side a, the altitude of the triangle is________.
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 457
Question
Two cubes have their volumes in the ratio 1: 64. Find the ratio of their surface areas.
Choices
Choice (4)  Response  

a.  1: 9 

b.  16: 3 

c.  7: 9 

d.  1: 16 

Question number: 458
Question
The radius of a cylinder is tripled but its lateral surface area is unchanged. Then its height must be________.
Choices
Choice (4)  Response  

a.  Halved 

b.  One third 

c.  Doubled 

d.  Constant 

Question number: 459
Question
A cylindrical tower is 7 meters in diameter and 15 meters height. The cost of white washing its curved surface at 75 paisa per is
Choices
Choice (4)  Response  

a.  257 

b.  250 

c.  240 

d.  247 

Question number: 460
Question
A hoop is resting vertically at staircase as shown in the diagram. AB = 8 cm and BC = 4 cm. The radius of the hoop is________.
Choices
Choice (4)  Response  

a.  12 cm 

b.  10 cm 

c.  14 cm 

d.  11 cm 
