Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q1.  Thrice the age of A is 7 times B's age. And C’s age is half of A's age. Also, nine years ago, A's age was onethird of B’s age then. What is the ratio between the age of the A,B and C age respectively ? 
1)  11:6:7  2)  11:6:3 
3)  14:6:3  4)  14:6:7 
5)  None of these 
Answer : 14:6:7
Explanation : Given, 3A = 7B
Explanation : Given, 3A = 7B
or 3A  7B = 0 (I) and A = 2C  (II)
And A9 = (B9)/3
or 3A27 = B9
or 3A  B = 18  (III)
from equations I and III , we get B = 3
A= 7 and C = 3.5
So, ratio of A,B and C i.e. A:B:C= 14:6:7
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Q2. 

1)  33 years  2)  40 years 
3)  43 years  4)  48 years 
5)  None of these 
Answer : 43 years
Explanation :
Explanation :
Present age of C = 85 – 7 = 78 years
Present age of B = 78 – 12 = 66 years
Present age of A = 3
11 66 = 18 years
Present age of A’s father = 18 + 25 = 43 years
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Q3. 

1)  30 yrs  2)  24 yrs 
3)  18 yrs  4)  36 yrs 
5)  None of these 
Answer : 30 yrs
Explanation : The present age of C = 72  42 = 30 years
Explanation : The present age of C = 72  42 = 30 years
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Q4. 

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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Q5. 

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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Q6. 

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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Q7. 

1)  29 yrs  2)  35 yrs 
3)  31 yrs  4)  33 yrs 
5)  None of these 
Answer : 31 yrs
Explanation :
Explanation :
Let, the present ages of A and B be 2x years and 3x years respectively.
So, (2x4)/(3x4) = 5/8
or 16x  32 = 15x 20
or x = 12
Therefore, the Ages of A after 7 years = 2x + 7 = 2 x 12 + 7 = 31 years
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Q8. 

1)  30 yrs  2)  24 yrs 
3)  18 yrs  4)  36 yrs 
5)  None of these 
Answer : 30 yrs
Explanation : The present age of Vijay = 72  42 = 30 years
Explanation : The present age of Vijay = 72  42 = 30 years
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Q9. 

1)  20 years  2)  22 years 
3)  18 years  4)  24 years 
5)  None of these 
Answer : 20 years
Explanation :
Explanation :
Let the shalini's and Sonal's present ages be 11x and 13 x years respectively.
After 3 years
13x + 3 = 29 or 13x = 29  3 = 26
X = 36/18 = 2
Shalini's age 2 years ago.
11x 2 = 11 x 2  2 = 20 years.
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Q10. 

1)  1 year  2)  2 year 
3)  25 year  4)  Can't be determined 
5)  None of these 
Answer : Can't be determined
Explanation :
Explanation :
Given that,
The difference of age R and Q = The difference of age Q and T.
Sum of age of R and T is 50 i.e. (R + T) = 50.
Then, R  Q = Q  T
or (R + T) = 2Q
Now given that, (R + T) = 50
So, 50 = 2Q and therefore Q = 25.
Question is (R  Q) = ?
Here we know the value(age) of Q (25), but we don't know the age of R.
Therefore, (RQ) cannot be determined.
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