The present age of a father is three times the age of his son. Five years ago, father's age was four times the age of the son. What is the present age of son?

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 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 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 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 the present ages of two person be 4x and 7x years respectively; then according to question,
7x = 30 + 4x
? 3x = 30
? x = 10
Hence, sum of their ages = 4x + 7x = 11x = 11 x 10 = 110 years

Let the present ages of Shami, Nammi and pammi are 3x, 4x and 5x years respectively;
then, According to question,
3x + 4x + 5x = 48
? 12x = 48
? x= 4
Hence, their present ages are 12, 16 and 20 years respectively.
So, required ratio = (12 + 8) : (16 + 8) : (20 + 8) = 20 : 24 : 28 = 5 : 6 : 7

Let us assume the present age of Ram R, Shyam S and Mohan M.
5 years ago, Ram age = R - 5
5 years ago, Shyam age = S - 5
5 years ago, Mohan age = M - 5
According to question,
5 years ago, the average age of Ram and Shyam was 20 years,
(5 years ago, Ram age + 5 years ago, Shyam age) /2 = 20
(R - 5 + S - 5 )/2 = 20
R + S = 40 + 10 = 50 ................(1)
Now Again according to question,
Now , the average age of Ram, Shyam and Mohan is 30 years
(R + S + M)/3 = 30
R + S + M = 90
Pu the value of R + S from equation (1)
50 + M = 90
M = 90 - 50 = 40
The present age of Mohan = 40 years
10 years hence, the age of Mohan = 40 + 10 = 50 years

Let us assume the present age of the subordinate is P then her subordinate age will be (P + 16).
According to Question,
Four years ago, the respective ratio of the ages of the boss and subordinate was 11 : 7.
(P +16 - 4 )/ (P - 4) = 11/7
? 7 x (P +16 - 4 ) = 11 x (P - 4)
? 7 x (P +12 ) = 11 x (P - 4)
? 7P + 84 = 11P - 44
? 4P = 128
? P = 32 years

According to question ,
The average age of a cricket team = 27 years
Age of two old players = 24 + 27 = 51
Age of two new players = 23 + 28 = 51
? New average age of a cricket team = 27 + ( Age of two old players ) - ( Age of two new players )
New average age of a cricket team = 27 + ( 51 ) - ( 51 ) = 27 years
In other words ,The total age of the two players which were replaced is the same as that of the total age of two players which replaced them. Therefore, the new average will remain unchanged.