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civil Maths

Maths : Problems on Age (Solved in Steps)

1. A man’s age is 125% of what it was 10 years ago, but 83 1/3 % of what it will be after ten 10 years. What is his present age?

A.70

B.60

C.50

D.40

Answer : Option C

Explanation :

Let the age before 10 years = x
Then 125x/100 = x + 10
=>125x = 100x + 1000
=> x = 1000/25 = 40
Present age = x + 10 = 40 +10 = 50


2. Ten years ago, R was half of S in age. If the ratio of their present ages is 3:4, what will be the total of their present ages?

A. 45

B. 40

C. 35

D. 30

Answer: Option C

Explanation :

Let the present age of R and S be 3x and 4x respectively. Ten years ago, R was half of S in age
=> (3x – 10) = ½ (4x – 10)
=> 6x – 20 = 4x – 10
=> 2x = 10
=> x = 5
total of their present ages = 3x + 4x = 7x = 7 × 5 = 35


3. Father is aged three times more than his son Anil. After 8 years, he would be two and a half times of Anil’s age. After further 8 years, how many times would he be of Anil’s age?

A. 4 times

B. 5 times

C. 2 times

D. 3 times

Answer: Option C

Explanation :

Assume that Anil’s present age = x.
Then father’s present age = 3x + x = 4x
After 8 years, fathers age = 2 ½ times of Anils’ age
=> (4x+8) = 2 ½ × (x+8)
=> 4x + 8 = (5/2) ×(x + 8)
=> 8x + 16 = 5x+ 40
=> 3x = 40-16 = 24
=> x = 24/3 = 8
After further 8 years,
Anil’s age = x + 8+ 8 = 8+8+8 = 24
Father’s age = 4x + 8 + 8 = 4 × 8 + 8 + 8 = 48
Father’s age/Anil’s age = 48/24 = 2


4. A man is 24 years older than his son. In two years, his age will be twice the age of his son. What is the present age of his son?

A.23

B.22

C.21

D.20

Answer : Option B

Explanation :

Let the present age of the son = x years
Then present age the man = (x+24) years
Given that in 2 years, man’s age will be twice the age of his son
=> (x+24) +2 = 2(x+2)
=> x = 22


5. Present ages of Kiran and Syam are in the ratio of 5 : 4 respectively. Three years hence, the ratio of their ages will become 11 : 9 respectively. What is Syam’s present age in years?

A.28

B.27

C.26

D.24

Answer : Option D

Explanation :

Ratio of the present age of Kiran and Syam = 5 : 4
=> Let the present age of Kiran = 5x
Present age of Syam = 4x
After 3 years, ratio of their ages = 11:9
=> (5x + 3) : (4x + 3) = 11 : 9
=> (5x+3) / (4x+3) = 11/9
=> 9(5x + 3) = 11(4x + 3)
=> 45x + 27 = 44x + 33
=> x = 33-27 =6
Syam’s present age = 4x = 4×6 = 24


6. The sum of ages of 5 children born at the intervals of 3 years each is 50 years. Find out the age of the youngest child?

A. 6

B.5

C.4

D.3

Answer : Option C

Explanation :

Let the age of the youngest child = x
Then the ages of 5 children can be written as x,
(x+3), (x+6),(x+9) and (x+12)
X + (x+3) + (x+6) + (x+9) + (x+12) = 50
=> 5x + 30 =50
=> 5x = 20
=> x = 20/5 = 4


7. A is two years older than B who is twice as old as C. The total of the ages of A, B and C is 27. How old is B?

A.10

B.9

C.8

D.7

Answer : Option A

Explanation :

Let the age of C = x. Then
Age of B = 2x
Age of A = 2 + 2x
The total age of A,B and C =27
=> (2+2x) + 2x + x = 27
=> 5x = 25
=> 25/5 = 5
B’s age = 2x = 2×5 = 10


8. The Average age of a class of 22 students is 21 years. The average increased by 1 when the teacher’s age also included. What is the age of the teacher?

A. 48

B. 45

C. 43

D. 44

Answer : Option D

Explanation :

Total age of all students = 22×21
Total age of all students + age of the teacher = 23 × 22
Age of the teacher = 23×22 – 22×21 = 22(23-21) = 22×2 = 44


9. A father said to his son, “I was as old as you are at the present at the time of your birth”. If the father’s age is 38 years now, what was the son’s age five
years back?

A. 20 years

B. 18 years

C. 14 years

D. 22 years

Answer : Option C

Explanation :

Let the son’s present age be x years.
Then, (38 – x) = x
=> 2x = 38
=> x = 38/2 = 19
Son’s age 5 years back = 19-5 = 14


10. Ayisha’s age is 1/6th of her father’s age. Ayisha ‘s father’s age will be twice the age of Shankar’s age after 10 years. If Shankar’s eight birthdays was celebrated two years before, then what is Ayisha ‘s present age?

A. 10 years

B. 18 years

C. 8 years

D. 5 years

Answer : Option D

Explanation :

Consider Ayisha’s present age = x
Then her father’s age = 6x
Given that Ayisha ‘s father’s age will be twice the age of Shankar’s age after 10 years
=> Shankar’s age after 10 years = ½ (6x + 10) =
3x + 5
Also given that Shankar’s eight birthdays was celebrated two years before =>
Shankar’s age after 10 years = 8 + 12 = 20
=> 3x + 5 = 20
=> x = 15/3 = 5
=> Ayisha ‘s present age = 5 years


11.The sum of the present ages of a son and his father is 60 years. Six years ago, father’s age was five times the age of the son. After 6 years, what will be son’s age?

A 23 years

B. 22 years

C. 21 years

D. 20 years

Answer : Option D

Explanation :

Let the present age of the son = x, then
Present age of the father = 60-x
Six years ago father’s age was 5 times the age of the son
=> (60-x)-6 = 5(x-6)
=> 84 = 6x
=> x = 84/6 = 14
Son’s age after 6 years = x + 6 = 14 + 6 = 20


12.Kiran is younger than Bineesh by 7 years and their ages are in the respective ratio of 7 : 9, how old is Kiran?

A. 25

B. 24.5

C. 24

D. 23.5

Answer : Option B

Explanation :

Let the ages of Kiran and Bineesh are 7x and 9x respectively
7x = 9x-7
=> x = 7/2 = 3.5
Kiran’s age = 7x = 7 × 3.5 = 24.5


13.Six years ago, the ratio of the ages of Vimal and Saroj was 6 : 5. Four years hence, the ratio of their ages will be 11 : 10. What is Saroj’s age at present?

A. 18

B. 17

C. 16

D. 15

Answer : Option C

Explanation :

Given that , six years ago, the ratio of the ages of Vimal and Saroj = 6 : 5
Hence we can assume that
The age of Vimal six years ago = 6x
The age of Saroj six years ago = 5x
After 4 years, the ratio of their ages = 11 : 10
=> (6x+10) / (5x + 10) = 11/10
=> 10(6x + 10) = 11(5x + 10)
=> 5x = 10
=> x = 10/5 = 2
Saroj’s present age = 5x + 6 = 5×2 +6 = 16


14.One year ago sunu’s & Manu’s age was 6:7 respectievely. Four years hence, the ratio would become 7:8. How old is sunu ?

A. 31

B. 36

C. 37

D. 30

Answer : Option A

Explanation :

Let sunu’s & manu’s ages one year ago be 6x & 7x years respectively. Then sunu’s age four years hence
= (6x+1)+4=6x+5 years
Manu’s age four years hence= (7x+1)+4=7x+5 years
ie 6x+5/7x+5=7/8
=> 8(6x+5)=7(7x+5)
=> 48x+40=49x+35
=> 49x-48x=40-35
=> x=5
hence sunu’s present age is=6x+1 = 6×5+1=30+1=31 years


16.My brother is 3 years elder to me. My father was 28 years of age when my sister was born while my mother was 26 years of age when I was born. If my sister was 4 years of age when my brother was born, then what was the age my father when my brother was born?

A. 35

B. 34

C. 33

D.32

Answer : Option D

Explanation :

Let my age = x
Then My brother’s age = x + 3
My mother’s age = x + 26
My sister’s age = (x + 3) + 4 = x + 7
My Father’s age = (x + 7) + 28 = x + 35
=> age my father when my brother was born = x + 35 – (x + 3) = 32


17.The present ages of A,B and C are in proportions 4 : 7 : 9. Eight years ago, the sum of their ages was 56. What are their present ages (in years)?

A. Insufficient data

B. 16, 30, 40

C. 16, 28 40

D. 16, 28, 36

Answer : Option D

Explanation :

Let’s take the present age of A, B and C as 4x, 7x and 9x respectively
Then (4x – 8) + (7x – 8) + (9x – 8) = 56
=> 20x = 80
=> x = 4
Hence the present age of A, B and C are 4×4,
7×4 and 9×4 respectively
ie, 16,28 and 36 respectively.


18.A person’s present age is two-fifths of the age of his mother. After 8 years, he will be one-half of the age of his mother. What is the present age of the mother?

A.60

B. 50

C. 40

D.30

Answer : Option C

Explanation :

Let the present age of the person = x .
Then present age of the mother = 5x/2
Given that , after 8 years, the person will be onehalf of the age of his mother.
=> (x + 8) = (1/2)(5x/2 + 8)
=> 2x + 16 = 5x/2 + 8
=> x/2 = 8
=> x = 16
Present age of the mother = 5x/2 = 5×16/2 = 40


19.A is as much younger than B and he is older than C. If the sum of the ages of B and C is 50 years, what is definitely the difference between B and A’s age?

A. Inadequate data

B. 3

C. 2

D. 5

Answer : Option A

Explanation :

Age of C < Age of A < Age of B
Given that sum of the ages of B and C is 50 years.
=> Let’s take B’s age = x and C’s age = 50-x
Now we need to find out B’s age – A’s age. But we cannot find out this with the given data.


20.Sobha’s father was 38 years of age when she was born while her mother was 36 years old when her brother four years younger to her was born. What is the difference between the ages of her parents?

A. 6

B. 5

C. 4

D. 12

Answer : Option A

Explanation :

Let Sobha’s age = x and her brother’s age = x-4
Then Sobha’s father’s age = x + 38
Sobha’s mother’s age = (x-4) + 36
=> Sobha’s father’s age – Sobha’s mother’s age = (x + 38) – [(x-4) + 36]
= x + 38 –x +4 – 36 = 6


21.The age of father 10 years ago was thrice the age of his son. Ten years hence, father’s age will be twice that of his son. What is the ratio of their present ages?

A. 7 : 3

B. 3 : 7

C. 9 : 4

D.4 : 9

Answer : Option A

Explanation :

Let the age of the son before 10 years = x and age of the father before 10 years = 3x
Now we can write as (3x + 20) = 2(x + 20)
=> x = 20
=> Age of Father the son at present = x + 10 = 20 + 10 = 30
Age of the father at present = 3x + 10 = 3×20 + 10 = 70
Required ratio = 70 : 30 = 7 : 3


22.The ages of two persons differ by 16 years. 6 years ago, the elder one was 3 times as old as the younger one. What are their present ages of the elder person?

A.10

B. 20

C. 30

D.40

Answer : Option C

Explanation :

Let’s take the present age of the elder person = x and the present age of the younger person = x – 16 (x – 6) = 3 (x-16-6)
=> x – 6 = 3x – 66
=> 2x = 60
=> x = 60/2 = 30


23.The present age of a father is 3 years more than three times the age of his son. Three years hence, father’s age will be 10 years more than twice the age of the son. What is father’s present age?

A.30

B.31

C. 32

D.33

Answer : Option D

Explanation :

Let the present age the son = x.
Then present age of the father = 3x + 3
Given that , three years hence, father’s age will be 10 years more than twice the age of the son
=> (3x+3+3) = 2(x + 3) +10
=> x = 10
Father’s present age = 3x + 3 = 3×10+ 3 = 33


24.Kamal was 4 times as old as his son 8 years ago. After 8 years, Kamal will be twice as old as his son. Find out the present age of Kamal.

A.40

B.38

C. 42

D.36

Answer : Option A

Explanation :

Let the age of the son before 8 years = x.
Then age of Kamal before 8 years ago = 4x
After 8 years, Kamal will be twice as old as his son
=> 4x + 16 = 2(x + 16)
=> x = 8
Present age of Kamal = 4x + 8 = 4×8 +8 = 40


25.If 6 years are subtracted from the present age of Ajay and the remainder is divided by 18, then the present age of Rahul is obtained. If Rahul is 2 years younger to Denis whose age is 5 years, then what is Ajay ‘s present age?

A.50

B.60

C. 55

D.62

Answer : Option B

Explanation :

Present age of Denis = 5 years
Present age of Rahul = 5-2 = 3
Let the present age of Ajay = x
Then (x-6)/18 = present age of Rahul = 3
=> x- 6 = 3×18 = 54
=> x = 54 + 6= 60


26.The ratio of the age of a man and his wife is 4:3. At the time of marriage the ratio was 5:3 and After 4 years this ratio will become 9:7. How many years ago were they married?

A.8

B.10

C. 11

D.12

Answer : Option D

Explanation :

Let the present age of the man and his wife be 4x and 3x respectively.
After 4 years this ratio will become 9:7
=> (4x + 4)/ (3x + 4) = 9/7
=> 28x + 28 = 27x + 36
=> x = 8
=> Present age of the man = 4x = 4×8 = 32
Present age of his wife = 3x = 3×8 = 24
Assume that they got married before t years.
Then (32 – t) / (24 – t) = 5/3
=> 96 – 3t = 120 – 5t
=> 2t = 24
=> t = 24/2 = 12


27.The product of the ages of Syam and Sunil is 240. If twice the age of Sunil is more than Syam’s age by 4 years, what is Sunil’s age?

A.16

B.14

C. 12

D.10

Answer : Option C

Explanation :

Let the age of Sunil = x and age of Syam = y.
Then xy = 240 —(1) 2x = y + 4
=> y = 2x – 4
=> y = 2(x – 2) —(2)
Substituting equation (2) in equation (1). We get x × 2(x-2) = 240
=> x (x-2) = 240/2
=> x (x -2) = 120 —(3)
We got a quadratic equation to solve. Always time is precious and objective tests measures not only how accurate you are but also how fast you are. We can either solve this quadratic equation in the traditional way. But the more easy way is just substitute the values given in the choices in the quadratic equation (equation 3 ) and see which choice satisfy the equation.
Here the option A is 10. If we substitute that value in the quadratic equation, x(x-2) = 10 × 8 which is not equal to 120
Now try option B which is 12. If we substitute that value in the quadratic equation, x(x-2) = 12 × 10 = 120.
See, we got that x = 12.
Hence Sunil’s age = 12


28.One year ago, the ratio of Sooraj’s and Vimal’s age was 6: 7 respectively. Four years hence, this ratio would become 7: 8. How old is Vimal?

A.32

B.34

C. 36

D.38

Answer : Option C

Explanation :

Let take the age of Sooraj and Vimal , 1 year ago as 6x and 7x respectively. Given that, four years hence, this ratio would become 7: 8.
=> (6x + 5)/(7x + 5) = 7/8
=> 48x + 40 = 49x + 35
=> x = 5
Vimal’s present age = 7x + 1 = 7×5 + 1 = 36


29.The total age of A and B is 12 years more than the total age of B and C. C is how many years younger than A?

A.10

B.11

C. 12

D.13

Answer : Option C

Explanation :

Given that A+B = 12 + B + C
=> A – C = 12 + B – B = 12
=> C is younger than A by 12 years


30.Sachin’s age after 15 years will be 5 times his age 5 years back. Find out the present age of Sachin?

A.10

B.11

C. 12

D.13

Answer : Option A

Explanation :

Let the present age of Sachin = x
Then (x+15) = 5(x-5)
=> 4x = 40
=> x = 10


31.Sandeep’s age after six years will be three-seventh of his father’s age. Ten years ago the ratio of their ages was 1 : 5. What is Sandeep’s father’s age at present?

A.30

B.40

C. 50

D.60

Answer : Option C

Explanation :

Let the age of Sandeep and his father before 10 years be x and 5x respectively. Given that Sandeep’s age after six years will be three-seventh of his father’s age
=> x + 16 = (3/7)(5x + 16)
=> 7x + 112 = 15x + 48
=> 8x = 64
=> x = 8
Sandeep’s father’s present age = 5x + 10 = 5×8 + 10 = 50