Mental AbilityBasic Arithmetic (NCO Cyber Olympiad Class 7): Questions 40  44 of 122
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Question number: 40
» Mental Ability » Basic Arithmetic
Question
The average age of 20 children in a class is 8 years. If the teacher’s age is included, the average age becomes 10 years. Find the teacher’s age.
Choices
Choice (4)  Response  

a.  50 

b.  42 

c.  45 

d.  35 

Question number: 41
» Mental Ability » Basic Arithmetic
Question
If the area of a triangle with base is equal to the surface area of a cube with length of edge , and then the altitude of the triangle is
Choices
Choice (4)  Response  

a. 


b.  a 

c. 


d. 


Question number: 42
» Mental Ability » Basic Arithmetic
Question
The ratio of the number of boys and girls in a college is 8: 9. If the percentage increase in the number of boys and girls were 20 % and 10 % respectively, what will be the new ratio?
Choices
Choice (4)  Response  

a.  96: 99 

b.  23: 24 

c.  8: 9 

d.  17: 18 

Question number: 43
» Mental Ability » Basic Arithmetic
Question
A cistern can be filled by two tapes A and B in 12 hours and 16 hours respectively. The full cistern can be emptied by a third tap C in 8 hours. If all the taps were turned on at the same time, in how much time will the empty cistern be filled up completely?
Choices
Choice (4)  Response  

a.  36 hours 

b.  40 hours 

c.  24 hours 

d.  48 hours 

Question number: 44
» Mental Ability » Basic Arithmetic
Question
If 20 men working 7 hours a day can do a piece of work in 10 days, in how days will 15 men working for 8 hours a day to do the same piece of work?
Choices
Choice (4)  Response  

a.  11.66 days 

b.  55 days 

c.  30 days 

d.  12 days 
