Answer: Data inadequate

Explanation:
1. The difference of age b/w R and Q = The difference of age b/w Q and T.
2. Sum of age of R and T is 50 i.e. (R + T) = 50.
Question: R - Q = ?.
Explanation:
R - Q = Q - T
(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. 

Answer: 22 years

Explanation:
Let the son's present age be x years. Then, man's present age = (x + 24) years.
(x + 24) + 2 = 2(x + 2)
x + 26 = 2x + 4
x = 22.

Answer: 14 years

Explanation:
Let the son's present age be x years. Then, (38 - x) = x
2x = 38.
x = 19.
Son's age 5 years back (19 - 5) = 14 years.

Answer: 16, 28, 36

Explanation:
Let their present ages be 4x, 7x and 9x years respectively.
Then, (4x - 8) + (7x - 8) + (9x - 8) = 56
20x = 80
x = 4.
Their present ages are 4x = 16 years, 7x = 28 years and 9x = 36 years respectively.

Answer: 10:1

Explanation:
Let the current age of Ajay and Vijay be 7x and 4x respectively.
(7x – 6) / 4x + 6 = 1/1
7x – 6 = 4x + 6
3x = 12
x = 4
Therefore, (7x + 12) / (4x – 12) = (7*4 + 12) / (4 * 4 -12) = 40/4 = 10/1

Answer: 36, 35

Explanation:
My brother was born 6 years after my sister was born and 3 years before I was born.
Age of father during my brother’s birth = (30 + 6) = 36 years.
Age of mother during my brother’s birth = (38 – 3) = 35 years.
Hence, during the birth of my brother, my father was 36 years old and my mother was 35 years old.