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 one-third 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 A-9 = (B-9)/3
or 3A-27 = B-9
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

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

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

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.

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.

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.

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, (2x-4)/(3x-4) = 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

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

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.

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, (R-Q) cannot be determined.
