The ratio of the ages of two persons is 4 : 7 and age of then is more than other by 30 years. The sum of their ages in years is:

Let us assume the present ages of son be Y then his father present age will be Y + 34 years. then
12 years ago, father's age = Y + 34 -12
12 years ago, Son's age = Y - 12
Now according to question,
12 years ago, father's age was 18 times the age of his son. then
18( Y - 12 ) = Y + 34 - 12
? 18Y - 216 = Y + 22
? 17Y = 238
? Y = 14
Hence, present age of his son = 14 years.

Let the present ages of Suresh and his daughter be 2x and x years respectively; then
According to question,
Six years hence, the ratio of their ages would be 23 : 13
(2x + 6) / (x + 6) = 23/13
? (2x + 6) 13 = 23 (x + 6)
? 26x + 78 = 23x + 138
? 3x = 60
? x = 20
Hence, present age of Suresh = 2 x 10 = 40 years

Let the present ages of Samir and Saurabh are 8a and 15a years respectively ; .
After 9 years the ages of Samir and Saurabh will be 8a + 9 and 15a + 9.
According to question,
After 9 years the ratio of their ages will be 11 : 18, then
(8a + 9)/ = 11/18
? (8x + 9) x 18 = 11 x (15a + 9)
? 144a + 162 = 165a + 99
? 21a = 63
? a = 3
Hence, difference of their ages = 15a - 8a = 7a = 7 x 3 = 21 years

Suppose, the age of Nikhil is 1 year.
Nikhil is 8 years younger than his brother Rohan.
Therefore, age of Rohan = 1 + 8 = 9 years
After 7 years ,
Nikhil will be 8 years old and Rohan will be 16 years old.

Let us assume the age of second son be Y, then age of first son will be Y + 10 and age of father will be (Y + 10 + 30) years respectively;
then according to question,
sum of their ages be 95 years.
x + x + 10 + x + 10 + 30 = 95
? 3x = 95 - 50
? 3x = 45
? x = 15
age of the father = x + 10 + 30
Hence, age of the father = 15 + 10 + 30 = 55 years.

Let us assume the present age of son be x then present of Deepak be 3x.
Five years hence, the ratio of their ages will be 34 : 13 respectively.
then according to question,
(3x + 5)/(x + 5) = 34/13
? (3x + 5) 13 = 34 (x + 5)
? 39x + 65 = 34x + 170
? 5x = 105
? x = 21
Hence, present age of Deepak = 3x = 3 x 21 = 63

Let the present ages of mother and her daughter are ( x + 25 ) and x years respectively ;
then Five years ago, the age of the mother was 6 times the age of the daughter.
6( x - 5 ) = x + 25 - 5
? 6x - 30 = x + 20
? 5x = 50
? x = 10
Hence, the age of the mother = 10 + 25 = 35 years

Let us assume the present ages of P and Q be (x + 4) and x years;
then, According to question,
( x + 4 + 5 )/ (x + 5) = 9/8
? 8x + 72 = 9x + 45
? x = 27
Hence, present age of P = 27 + 4 = 31 years

Let us assume that present age of son is P years then his father's present age will be 3P.
According to question,
Five years ago, father's age was four times the age of the son.
Then
4 (P - 5) = 3P - 5
? 4P - 20 = 3P - 5
? P = 15 years
The present age of Son is 15 Years.