From the given statements A, B & C

Let the present age of Teja = P

Raju present age = P + 4

Sita’s present age = 2(P + 4)

Average of ages of Sita & Teja = 19

=> (2P + 8 + P)/2 = 19

= 3P + 8 = 38

=> P = 30/3 = 10

Hence, the present age of Teja = P = 10 yrs.

Therefore, by using all the three statements A, B & C we can find the age of Teja.

According to the given data,

(V + R)/2 = 24

Now, after joining of Veerender,

V + R + D)/3 = 25.5

Hence, Veerender Age = 3(25.5) – 2(24) = 76.5 – 48 = 28.5 years.

Let the present ages of the mother and daughter be 2x and x years respectively.
Then, (2x – 18) = 3(x – 18) => x = 36
Required sum = (2x + x) = 108 years.

Present age of Sony = 24 + 4 = 28 years

After 5 years Renuka’s age = 7×5 + 5 = 40 years

Let the age of sushma be x and
the age of her son is y
Then five years before x-5=5(y-5) …(1)
Five years hence x+5 = 3(y+5)-8 …..(2)

By soving (1) & (2), we get
5y – 15 = 3y + 7
y = 11 => x = 35

Therefore, the age of Sushma = 35 and her son = 11.

Let number of boys = x  , Let number of girls = y
Total numbers of students = x + y
(x + y) × 15.8 = 16.4x + 15.4y
0.6x = 0.4y
x/y = 0.4/0.6 = 2/3

Ratio of boys and girls in the class is 2:3

Given sum of present ages of A, B, C & D

A + B + C + D = 176

and also given that,

(A-4) : (B-4) : (C-4) : (D-4) = 11 : 9 : 6 : 14

Let the ratio = x

=> A-4 + B-4 + C-4 + D-4 = 11x + 9x + 6x + 14x

=> (A + B + C + D ) – 16 = 40x

=> 176 – 16 = 40x

=> x = 4

=> A = 44 + 4 = 48

=> B = 40

=> C = 28

=> D = 60

Therefore, from the above conclusions

D is eldest with 60 years and C is youngest with 28 years of ages.

The ratio of X and Y ages at present is 4:5.

Then, the ratio 20 years ago will not be more than the ratio at present.

So, from the options 9:10 is not satifying => its ratio is 0.9 which is greater than presnt ratio of 0.8.

Let Karan’s present age be x years and Shiva’s present age be y years.
Then, according to the first condition,
x – 10 = 3(y – 10) or x – 3y = – 20 ..(1)
Now, Karan’s age after 10 years = (x + 10) years
Shiva’s age after 10 years = (y + 10)
(x + 10) = 2 (y + 10) or x – 2y = 10 ..(2)
Solving (1) and (2), we get x = 70 and y = 30
Karan’s age = 70 years and Shiva’s age = 30 years.

Let the Present age of the son be P, which means he was born P years ago.At the time the son was born, the age of the man was : (48 – P). So, according to the statement made by the man, his age when the son was born should be equal to 2/3 of P.

Therefore, 

Solving, we get P = 28.8 years; which is the present age of the son.

Let Shilpa’s present age is p years

According to question,

p = 4(x+4) – 4(x–4)

p = 4x+16 – 4x+16

p = 32

Shilpa’s present age = 32 years

Rajeev is four years older than Shilpa

=> Shilpa’s present age = Rajeev’s age 4 years before.

=> Rajeev’s age 4 years before = 32 years.

Let us consider Karthik as K1 and Kalyan as K2.

Given k18+k1k18+k1 and K2 – (K1 + 5) = 3

K2 – K1 = 8

K2 = 8 + K1

Now,

k18+k1= 45k18+k1= 45

=> K1 = 32 years

Therefore K2 = 40 years.

K1 + K2 = 72 years.

Let present ages of Sumit=w, Krishna=x, Rishabh=y and Rohit=z , then
w+x+y = 43×3 = 129 —(i) and
w+y+z = 49×3 = 147 —(ii)
Subtracting (i) from (ii), (w+y+z) – (w+x+y)=147 -129 , z- x =18 —(iii)
Given Rohit’s age => z = 54, so from (iii), x = 54-18 = 36

Raj Tarun’s age = 0 when he was born.
Then, given his brother is 6 years old.
Then his father is 6 + 32 = 38 when Raj Tarun was born
And his mother is 3 years yonger than his father => so his mother was 35 years old when Raj Tarun was born
and his sister is 25 year younger than his mother
so Raj Tarun’s sister was 10 years old when Raj Tarun was born.

Let varun’s age = x yrs.

From the given conditions,

x+1  =  2(x-12)

x = 25 years.