Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q81.  Directions : Study the graphs carefully to answer the questions that follow: Total number of children in six different schools and the percentage of girls are give bellow in the linechart.What is the average number of boys in schools P and Q together ? 
1)  1365  2)  1475 
3)  1575  4)  1625 
5)  None of these 
Answer : 1575
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Q82.  Directions : Study the graphs carefully to answer the questions that follow: Total number of children in six different schools and the percentage of girls are give bellow in the linechart. What is the ratio of the number of girls in school Q to the number of girls in school P ? 
1)  20 : 27  2)  20 : 23 
3)  27 : 20  4)  D.I 
5)  17 : 20 
Answer : 27 : 20
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Q83. 

1)  162/3%  2)  25% 
3)  331/3%  4)  35% 
5)  None of these 
Answer : 331/3%
Explanation : A’s investment in 2004 is Rs. 80 lakh.
Explanation : A’s investment in 2004 is Rs. 80 lakh.
A’s investment in 2003 is Rs. 60 lakh.
So, percentage rise = [(80  60)/60] x100 = 33.33%
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Q84. 

1)  15%  2)  162/3% 
3)  18%  4)  20% 
5)  None of these 
Answer : 162/3%
Explanation : The investment of B in 2001 is 60 lakh and investment in 2004 is 70 lakh .
Explanation : The investment of B in 2001 is 60 lakh and investment in 2004 is 70 lakh .
So, % increased = [(70  60)/60] x 100 = 100/6 = 50/3 =16.66%
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Q85. 

1)  4 years  2)  6 years 
3)  8 years  4)  12 years 
5)  None of these 
Answer : 6 years
Explanation :
Explanation :
Mother's age when Prasant's brother was born = 46 years.
Father's age when Prasant's brother was born = (48 + 4) years = 52 years.
Required difference = (52  46) years = 6 years.
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Q86. 

1)  16 years  2)  18 years 
3)  20 years  4)  24 years 
5)  None of these 
Answer : 20 years
Explanation :
Explanation :
Let, the present ages of Alok and Prakash be x and (60 x) years respectively.
Then, (60  x)  6 = 5(x  6)
54  x = 5x  30
or 6x = 84
or x = 14.
So, Prakash's age after 6 years = (x+ 6) = 20 years.
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Q87. 

1)  14 years  2)  19 years 
3)  24 years  4)  28 years 
5)  None of these 
Answer : 19 years
Explanation :
Explanation :
Let, B's present age be x years. Then, (48  x) = x
Or 2x = 48.
Or x = 24.
B's age 5 years back (24  5) = 19 years.
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Q88.  There are 5 men and 3 women to form a committee of 5members where at least 3 men are there. How many way they can be selected ? 
1)  42  2)  45 
3)  46  4)  54 
5)  None of these 
Answer : 46
Explanation : Total ,5 men and 3 women i.e. 8 persons.
Explanation : Total ,5 men and 3 women i.e. 8 persons.
So, 3 men can selected from 5 men.
They can selected in (^{5}C_{3}_{ }x ^{3} C_{2} ) or (^{5}C_{4}_{ }x^{ 3} C_{1} ) or (^{5}C_{5}_{ }x ^{3 }C_{0} )
Total numbers of way to select = [(5 x 4 )/2 x 3 ] +[(5 ) x 3 ] + [(1x 1) ] = 46
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Q89.  The sum of two numbers is 27 and their H.C.F is 3. If one of the number is lies between 13 to 16, the find the value of the other number ? 
1)  12  2)  15 
3)  18  4)  24 
5)  None of these 
Answer : 12
Explanation : Let, two numbers are 3x and 3y respectively.
Explanation : Let, two numbers are 3x and 3y respectively.
Then, 3x + 3y = 27
or 3 (x + y) = 27
or (x + y) = 27/3 = 9
So, pairs of numbers are 9 = (1,8) , (2,7) , ( 3,6) and (4,5) .
Thus the numbers are 3 x 4 = 12 and 3 x 5 =15
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Q90. 

1)  Rs.820  2)  Rs.890 
3)  Rs.1020  4)  Rs.1250 
5)  None of these 
Answer : Rs.890
Explanation :
Explanation :
A : B : C = (8,000 x 6) : (4,000 x 8) : (8,000 x 8) = 48 : 32 : 64 = 3 : 2 : 4.
B's share = ( Rs. 4005/9) x 2 = Rs. 890.
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