Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q51. 

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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Q52. 

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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Q53. 

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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Q54.  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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Q55.  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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Q56. 

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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Q57. 

1)  Rs.1200  2)  Rs.1250 
3)  Rs.1450  4)  Rs.1500 
5)  None of these 
Answer : Rs.1500
Explanation :
Explanation :
Let, the total profit be Rs. 100.
After paying to charity, A's share = (Rs. 95 /5)x 3 = Rs. 57.
If A's share is Rs. 57, total profit = Rs. 100.
If A's share Rs. 855, total profit = ( 855/57) x100 = 1500
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Q58. 

1)  4 : 5  2)  5 : 4 
3)  3 : 2  4)  Data Inadequate 
5)  None of these 
Answer : 5 : 4
Explanation :
Explanation :
C.P. = S.P.  Profit
or C.P. = 5 1 = 4
or S.P. : C.P. = 5 : 4
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Q59. 

1)  Rs. 4,250  2)  Rs. 4,500 
3)  Rs. 6,400  4)  Rs. 7200 
5)  None of these 
Answer : Rs. 7200
Explanation :
Explanation :
We know that Sum = (S.I X 100 )/ R X T
= (Diff. in S.I X 100 ) / Diff. in rate X Time
= (72 X100)/ 2 X 5 = Rs. 7200.
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Q60. 

1)  5: 17  2)  1:11 
3)  11:1  4)  2:3 
5)  None of these 
Answer : 11:1
Explanation :
Explanation :
By alligation method :
2.40 3.60
2.50
3.60  2.50 2.50  2.40
= 1.10 10
So, Ratio will be 11 : 1.
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